1 Suit No 610 of 2013 (“the Suit”) arises from a dispute between a contractor and a sub-contractor over alleged defects in architectural rain screen roof panels (hereafter the “GRP panels”) that had been installed on the Marina Bay Sands Integrated Resort Development (“the Development”). The GRP panels were constructed of glass fibre-reinforced skins that enveloped an aluminium honeycomb. The dispute centred first on whether and to what extent the bottom or lower skins (hereafter the “inner skins”) of the GRP panels had “delaminated” (ie, come apart) from the aluminium honeycomb, and secondly, whether the GRP panels met the fire safety requirements of the contract.

2 One unusual feature of this case is that, unlike the usual construction disputes, there is not a single photograph showing a GRP panel with a delaminated inner skin. Nor is there any direct evidence, such as a GRP panel with its inner skin delaminated, preserved for viewing. Instead, I have had numerous test reports placed before me to “prove” inner skin delamination had occurred, as well as factual and expert witnesses describing sounds emanating from the GRP panel when it was walked upon, “sponginess” when stepped upon, or coring which produced samples with inner skins of the sample core fully or partially delaminated or fully intact. Based on this evidence, I am asked to conclude, on a balance of probabilities, whether delamination of the inner skins occurred. (As for the core samples, the plaintiff no longer relies on them as evidence of delamination.)

3 Having considered the evidence before me and the parties’ submissions, I dismiss the plaintiff’s claim. My reasons for so doing and my key findings are set out at [451] below.

4 The plaintiff, Kalzip Asia Pte Ltd (“Kalzip”) (previously known as Corus Building Systems Pte Ltd), is a limited private company established under the laws of Singapore. It is a subsidiary of Kalzip Business Unit, which was part of the Distribution and Building Systems Division within the Corus Group, now part of Tata Steel Europe Ltd (“Tata Steel”). It carries on the business of, inter alia, manufacturing, processing, importing, exporting and storing aluminium roofing and wall cladding systems.

5 The defendant, BFG International Limited (“BFG”), is a company incorporated in the Kingdom of Bahrain and in the business of manufacturing fibre-reinforced composite products. ¹ These products are used for a wide variety of purposes, such as aircraft components, airport counters, railcar and aircraft toilet modules, storage tanks and building cladding. ²

6 On 28 May 2008, Kalzip signed a Trade Contract with Marina Bay Sands Pte Ltd (“MBS”), the owner and developer of the Development. MBS hired Kalzip as a Trade Contractor to provide a roofing system (“the Kalzip Roofing System”) for podium roof finishes works for three buildings in the Development, namely, the Meetings, Incentives, Conventions and Exhibitions (“MICE”), the theatre and the casino buildings. ³ These works comprised two curved roofing sections (each primarily comprising a weather-tight aluminium standing-seam roofing system) separated by a vertical clerestory. The upper section of the Kalzip Roofing System was to be overlain by architectural rain screen panels which were to be attached to a support rail system which was in turn fixed to the underlying Kalzip Roofing System. ⁴ I hereafter refer to the works pertaining to the Kalzip Roofing System as “the Project”. The value of Kalzip’s contract with MBS was S$28,709,317. ⁵

7 Pursuant to a Sub-Contract dated 28 August 2008, Kalzip engaged BFG to supply glass-reinforced plastic-faced aluminium panels at the cost of S$4,927,500 for the Project. ⁶ GRP panels are a type of fibre-reinforced plastic composite product, which is a product made of a polymer matrix reinforced with fibres. In this case the GRP panels were made of a 20mm-thick aluminium honeycomb core (19mm cell size) sandwiched and enveloped between two fire-retardant unsaturated polyester resin glass fibre reinforcements, or “skins”. ⁷ The upper skin additionally had a polyester gelcoat. ⁸ The panels measured about 3m wide and 10–14m long. ⁹ It is not disputed that the Sub-Contract comprised the following documents: ¹⁰

(a) a Purchase Order dated 28 August 2008, between Kalzip and BFG; ¹¹

(b) Annexure 1 to the Purchase Order, which incorporated: ¹²

(i) a document titled “BFG Comments on Specifications – Appendix 2 – R3 – 29 Aug 08.pdf”, containing BFG’s comments on the tender specifications for the Sub-Contract;

(ii) a document titled “Podium Roof GRP Deflection Matrix Summary_A_20Jun08.pdf”, dated 20 June 2008; and

(iii) a document titled “BFG – Corus – SANDS_Podium roof Price Table_300708.pdf”, dated 30 July 2008;

(c) Annexure 2 to the Purchase Order ¹³ ; and

(d) extracts from the Technical Specification for Podium Roof Finishes WP 3215: MICE Roof, Casino Roof & Theatre Roof, ISSUE_REV C, dated 23 August 2007 (“Specification Revision C”) ¹⁴ .

8 The Sub-Contract specifications which are pertinent to the Suit are: (1) the requirements as to the structural performance of the GRP panels, in terms of the load they would be able to bear and the degree to which they would deflect or bend under specified loads; and (2) requirements as to the fire safety of the GRP panels. I expand on these requirements at [50] and [391] below respectively.

9 The GRP panels were manufactured by BFG in the Philippines in the latter half of 2009. ¹⁵ They were manufactured based on information and manufacturing drawings (one drawing per panel) provided by Kalzip. ¹⁶ Throughout the manufacturing process, Kalzip’s appointed representative, Loxon Philippines Inc (“Loxon”), carried out a quality check on each GRP panel to ensure that it had been manufactured properly, that its dimensions were correct and that it was not delaminated, and thereafter approved it for shipment to Singapore for installation. ¹⁷ Kalzip installed the panels from around November 2009 on the casino building roof, followed by the MICE building roof from around January 2010; works on the theatre building roof were scheduled to commence in March 2010. ¹⁸

10 Sometime around January and February 2010, Kalzip complained that delamination of the GRP panels had been observed during installation on the casino and MICE building roofs. In particular, it was alleged that the inner skins of the GRP panels were coming apart from the aluminium honeycomb core. Surveys were carried out and delamination was allegedly found to be widespread. ¹⁹ According to Kalzip, the delamination adversely affected the load-bearing characteristics of the panels, rendering them non-compliant with the Sub-Contract requirements. ²⁰

11 BFG appeared to accept that delamination had occurred, but took the view that this was because the panels had been misused (viz, had been walked on and subjected to excessive loads). Kalzip, on the other hand, took the position that the panels had delaminated due to deficiencies in manufacturing. ²¹ An internal e-mail within BFG dated 7 March 2010 records that, the night before a meeting with MBS, Kalzip informed BFG that circular samples which had been cored from some GRP panels installed onsite were underweight. BFG protested that the panels had been misused. In response, Kalzip gave BFG “two options”. The first was for BFG to “go with [Kalzip] and support them to say to MBS that there is a problem and we will resolve this” in an attempt to “get out of this problem with minimum damage”. One of the risks associated with this option was that Kalzip wanted BFG to bear all the liability. The second option was for BFG to “start [an] argument [with Kalzip] about the misuse of panels versus bad manufacturing and go to [a] formal dispute between MBS and BFG where [Kalzip] would not support [BFG]”. This would involve BFG officially taking the position that the panels, as supplied, met the load bearing requirements in the Sub-Contract. ²²

12 BFG chose the former option. On 9 March 2010, BFG met with Kalzip and “re-iterated BFG’s commitment to assisting Kalzip with resolving the upstream issues with MBS and in particular on working together with Kalzip to rectify the alleged defects identified by MBS and/or Kalzip”. ²³ BFG and Kalzip sought to present a united front to MBS. The parties agreed to adopt the strategy of showing that the panels were strong enough to meet the Sub-Contract load requirements notwithstanding delamination of the lower skin. BFG carried out calculations to show that this was the case. Based on these calculations, BFG took the position that the GRP panels were fit for purpose and met the Sub-Contract requirements without modification even if they were delaminated, and presented this position to MBS on 17 March 2010. Kalzip likewise adopted this position vis-à-vis MBS. ²⁴ The less-than-satisfactory test results were explained by pointing out problems with the tests and the other components of the structures supporting the panels, and not the panels themselves.

13 Notwithstanding its position vis-à-vis MBS, Kalzip looked to BFG to make good its losses arising from the allegedly delaminated panels. At a meeting with MBS described in BFG’s 7 March e-mail, “[Kalzip] used this weak position and put [the] entire responsibility on BFG”. ²⁵ On 25 March 2010, Kalzip’s solicitors wrote to BFG alleging that the panels were “not manufactured in accordance with the specifications stated in the Purchase Orders” and that BFG was “clearly in breach” of the Sub-Contract. It reserved its right to recover, from BFG, sums that MBS had withheld from Kalzip under the Trade Contract. ²⁶ BFG replied on 6 April 2010 denying that the panels were defective and alleging that the delamination observed onsite had resulted from misuse and mishandling during and after installation. ²⁷ Kalzip sent another letter dated 25 May 2010 warning BFG that it was “currently facing a SGD 1 million to SGD 33 million claim, due to the supplied defective panels” [emphasis in original]. ²⁸

14 From March to November 2010, BFG continued to propose rectification solutions to Kalzip, including supplying replacement GRP panels. ²⁹ On 3 August 2010, Kalzip’s project director Mr Peter Carter (“Mr Carter”) e-mailed BFG’s Mr Flook for a quotation for replacement panels and sought confirmation that BFG would “absorb the costs for this work until such time as Kalzip resolves the financial implications of this matter with MBS”, following which “[a] solution would also then be worked out between Kalzip and BFG”. ³⁰ Mr Flook received a call from Mr Carter, who said that BFG “need to keep the aluminium core, and a percentage of the re manufacturing cost that BFG is prepared to bear. Then if [Kalzip] win[s] the case against MBS then they pay [BFG] back.” ³¹ On 13 November 2010, BFG offered to supply replacement GRP panels at Kalzip’s cost. ³² It did not hear back from Kalzip thereafter.

15 Notwithstanding the attempts to convince MBS that the GRP panels would perform satisfactorily even with delaminated inner skins, MBS lost confidence in the panels and took the decision to replace them with aluminium panels. ³³ Correspondence from July 2010 shows that MBS held Kalzip responsible for the delamination of the GRP panels and liable to make good any damage, loss or injury suffered by MBS arising therefrom. Kalzip made rectification proposals to MBS, but these were not implemented. ³⁴ Kalzip alleged that at a meeting on 18 November 2010, MBS informed Kalzip that it was not prepared for Kalzip to replace the GRP panels using BFG as the manufacturer as it had lost confidence in BFG. ³⁵ In February 2011, MBS sent another letter to Kalzip expressing disappointment in Kalzip and reserving its right to appoint third party contractors to carry out the rectification work. ³⁶ In March 2011, MBS issued a Construction Manager’s Instruction omitting the theatre panels from Kalzip’s scope of works. On 15 March 2011, MBS informed Kalzip that it had appointed a third party contractor to remove and replace the GRP panels in the Project. ³⁷ On 28 April 2011, MBS instructed a third party contractor, Craft Facade Pte Ltd (“Craft”), to remove the GRP panels and install replacement aluminium panels. ³⁸ Kalzip claims that it was not involved in the removal of the GRP panels or the instalment of replacement panels. ³⁹ After the panels were removed from the Project, they were stored in the Toll Warehouse in anticipation of their removal. ⁴⁰ The GRP panels which were meant to be installed on the theatre building were not installed as a result of the problems discovered with the MICE and casino buildings and remained in storage. Some of these panels were subsequently sent for testing though, for reasons which I detail below, the tests did not establish delamination. These panels were disposed of before the commencement of the Suit.

16 Kalzip claims that as a result of the alleged defects, MBS refused to pay Kalzip for the GRP panels already installed. MBS also deducted S$8,685,495.74 from Kalzip’s final account for the costs MBS had incurred in connection with the allegedly defective GRP panels (ie, for testing the GRP panels and engaging consultants and Craft). ⁴¹ Kalzip seeks that sum from BFG in the present proceedings.

17 On 4 July 2011, Kalzip commenced arbitration proceedings against MBS. As will be seen, Kalzip’s approach was to first deny liability for the delaminated GRP panels upstream vis-à-vis MBS, and to subsequently attempt to visit liability for the same upon BFG downstream. In relation to the GRP panels, Kalzip sought payment from MBS for inter alia supplying and installing GRP panels on the MICE and casino buildings; fabricating GRP panels for the theatre building; investigating remedial solutions and further work done in connection with the defective GRP panels; and loss of profit on the work of removal and replacement, which had been awarded to Craft. Kalzip also claimed other sums, including in relation to disputed variations which it had carried out, prolongation costs and the repayment of retention monies; these items were not related to the Kalizp-BFG Sub-Contract. ⁴² Its total claim against MBS was S$15,868,904.47, being the difference between the sums it claimed to be entitled to (S$42,368,556.51) and what it had been paid (S$26,499,652.04). ⁴³

18 Kalzip’s position in the arbitration was that it had complied with its contractual obligations, and that MBS bore design responsibility for the GRP panels, which were inherently prone to delaminate. Kalzip’s Statement of Claim in the arbitration states that the delamination occurred “as a result of design decisions made by [MBS], which were not [Kalzip’s] responsibility”, and that MBS wrongly refused to allow Kalzip to replace the defective panels unless Kalzip agreed to vary the contractual terms. ⁴⁴ Kalzip’s Reply and Defence to Counterclaim in the arbitration states that the “basic design of the GRP panels was complete” at the time that MBS issued the Letter of Award to Kalzip, and that the “tendency to delaminate was inherent in the design of the GRP Panels”. ⁴⁵

19 There were negotiations towards a settlement between MBS and Kalzip in the lead-up to the arbitration hearing. According to Kalzip, MBS remained unwilling to pay any sums to Kalzip for the defective GRP panels, though it indicated that it was willing to compromise on Kalzip’s variation claims. Kalzip says that as a matter of principle, MBS refused to compromise on its decision to deduct the sum of S$8,685,495.74 from monies due to Kalzip under the contract (comprising the contract sum paid by MBS to Craft (S$8,121,319.31), the consultancy fees incurred by MBS in connection with the defective GRP panels (S$449,950.75) and testing fees (S$114,225.68)). ⁴⁶ The arbitration hearing between Kalzip and MBS began on 18 February 2013 and was scheduled to last five weeks. On 23 February 2013, Kalzip and MBS entered into an in-principle commercial settlement, which they formally executed on 26 February 2013 (“the Settlement Agreement”); MBS agreed to pay Kalzip the sum of S$5.5m, of which S$4m was compensation and S$1.5m was for Kalzip’s agreed costs. MBS would also pay the costs of the arbitration proceedings. ⁴⁷

20 According to Mr Mueller, the S$4m essentially comprised all of Kalzip’s claims apart from those which had to do with the GRP panels. ⁴⁸ I note, however, that as stated in cl 1.1 of the Settlement Agreement, MBS paid Kalzip S$4m “in full and final settlement of any and all disputes, controversies, claims and counterclaims that each party has against the other”. Moreover, cl 8.1 of the Settlement Agreement states, “This Agreement constitutes the entire agreement between the parties in connection with its subject matter and supersedes all prior representations, communications, negotiations and understandings concerning the subject matter of this Agreement.” ⁴⁹ Kalzip’s claims against MBS in respect of the allegedly defective GRP panels were therefore part of the claims settled in the Settlement Agreement.

21 On 30 May 2013, Kalzip sent a letter of demand to BFG for the sum of S$13m. BFG claims that it was surprised by the letter of demand, having heard nothing from Kalzip since BFG’s offer in November 2010 to supply replacement GRP panels at Kalzip’s cost. BFG says it did not hear from Kalzip for close to three years and was left out of the loop regarding Kalzip’s arbitration with MBS. ⁵⁰ One of Kalzip’s witnesses confirmed during the trial that Kalzip did not inform BFG about its settlement with MBS prior to signing the Settlement Agreement. ⁵¹ There does not seem to be any evidence before me that BFG knew or was otherwise given notice that the panels were being removed from the Project. ⁵²

22 It does seem strange that after the flurry of accusations and denials of inner skin delamination in the GRP panels from January or February 2010 to November 2010, when BFG did not hear back from Kalzip on its offer to replace GRP panels at Kalzip’s cost, BFG appears to have sat tight. Although I note that BFG did not have an office in Singapore, there is no evidence before me as to whether they kept in touch with developments at the site or whether they hoped Kalzip would resolve matters with MBS. Under cross-examination, Mr Premamoorthy, BFG’s Vice President who managed the Philippines factory which produced the GRP panels (see [37(b)] below), agreed that from March 2010 through to May 2013, BFG knew that it might face potential liability to Kalzip. ⁵³ It therefore appears that BFG was aware of a potential dispute with Kalzip but perhaps adopted the attitude of letting sleeping dogs lie. Kalzip’s strategy, on the other hand, was inter alia to deny liability for the delaminated panels in its arbitration with MBS but, whether for tactical or other reasons, without involving BFG. Even though Kalzip was based in Singapore, knew about the panels being removed and replaced and had at the very least a sizeable portion of the panels in its possession, it did not test the panels for delamination or preserve them as evidence. Kalzip ended up settling its claim against MBS and, having obtained what it could from MBS, then turned to BFG in the present Suit to make a claim against BFG for the defective GRP panels and damages caused thereby. Although Kalzip alleges that MBS refused to pay for the GRP panels, I have noted earlier Kalzip’s settlement with MBS of its pleaded claims in the arbitration, including the supply and installation of roof finishes and GRP panels to the MICE and casino buildings, the supply of GRP panels and the supply and installation of roof finishes to the theatre building, the cost of investigating remedial solutions and further work done in connection with the defective GRP panels, and loss of profit on removing and replacing the same as a result of that work being awarded to Craft. ⁵⁴

23 On 11 July 2013, Kalzip commenced the Suit against BFG. The Suit has been bifurcated and these grounds of decision deal with BFG’s liability in the claim only. The quantum of damages would have been dealt with in a subsequent tranche had I allowed the claim.

24 Kalzip claims that BFG failed to produce GRP panels that met the structural performance requirements and fire safety requirements of the Sub-Contract. ⁵⁵

25 As regards the structural performance requirements, Kalzip claims that the GRP panels supplied by BFG suffered extensive inner skin delamination, which meant that they no longer met the deflection requirements in the Sub-Contract. As I have noted earlier, all the GRP panels from the Project were disposed of before the Suit, and testing them for inner skin delamination is no longer an option. No photographs were taken of the underside of the panels in situ or during removal as proof of delamination and no panels were sent for laboratory testing or otherwise investigated for inner skin delamination. ⁵⁶ To prove delamination, Kalzip relies on various site surveys performed in February and March 2010, as well as correspondence from BFG expressly acknowledging delamination. ⁵⁷ It alleges that the delamination occurred as a result of BFG’s failure to: ⁵⁸

(a) select or formulate the appropriate constituents of the GRP panels;

(b) properly design the GRP panels to avoid delamination;

(c) undertake or prescribe an appropriate manufacturing or assembly process; and

(d) take all necessary measures to ensure that the GRP panels supplied would comply with the structural performance and fire safety requirements.

26 BFG, on the other hand, denies that the panels ever delaminated. It claims that the reports of delamination in early 2010 were based on crunching sounds which emanated from the panels when walked upon, and that expert evidence shows that such sounds do not necessarily indicate delamination. ⁵⁹ It further relies on tests carried out in 2015 on GRP panels specially manufactured for that purpose, which were found not to be delaminated. Kalzip submits that these tests are not reliable because they did not involve GRP panels actually supplied to the Project. ⁶⁰ In the alternative, BFG submits that even if there was delamination, the delamination was attributable to Kalzip’s acts, in particular: ⁶¹

(a) mishandling of the panels by using them as working platforms for installation, failing to store them appropriately onsite, failing to put in place a proper installation process or system, and placing and/or storing heavy materials atop the panels;

(b) defective design of the support rail system, which did not provide adequate support to the GRP panels;

(c) failure to advise BFG about the loads imposed by the handling jigs to be used for the GRP panels;

(d) providing incomplete specifications which failed to: (i) take into account all the installation loads, (ii) provide for movement criteria for the Kalzip Roofing System and the support rails, and (iii) provide for any misalignment of the support rails;

(e) uneven release of the suction cups or uneven loading from misaligned rails, which would have imposed loads other than those specified in the Sub-Contract; and

(f) Kalzip personnel jumping on the GRP panels during the core sampling exercise.

27 BFG further contends that the GRP panels met the structural performance and deflection criteria in the Sub-Contract even if they were delaminated. They also were fit for the purpose for which they were bought, ie, to serve as architectural finish panels. ⁶²

28 The second component of Kalzip’s claim is that the GRP panels supplied by BFG failed to meet the fire safety requirements in the Sub-Contract. Sample GRP panels manufactured by BFG passed a suite of fire tests conducted from 2008 to 2010 (before the panels were installed). However, GRP panels which had been installed in the Project and then were subsequently removed for fire testing failed another suite of fire tests in 2011 to 2012. Kalzip relies on the 2011–2012 fire tests as evidence that the GRP panels failed to meet the fire safety requirements while BFG relies on the 2008–2010 fire tests as evidence that they met them. Each party submits that the fire tests relied on by the other party are unreliable.

29 Kalzip also avers that terms were implied into the Sub-Contract that the GRP panels supplied by BFG would: ⁶³

(a) correspond with the description of the GRP panels in the Sub-Contract, pursuant to s 13(1) of the Sale of Goods Act (Cap 393, 1999 Rev Ed) (“the SGA”);

(b) be of satisfactory quality, in that they would meet the standard that a reasonable person would regard as satisfactory, pursuant to s 14(2) read with s 14(2A) of the SGA; and

(c) be reasonably fit for their intended purpose under the Sub-Contract, pursuant to s 14(3) of the SGA.

30 Kalzip submits that, by failing to provide GRP panels which met the structural performance and fire safety requirements of the Sub-Contract, BFG failed to produce a product that met these terms. ⁶⁴ Although Kalzip originally pleaded terms implied under the Supply of Goods Act (Cap 394, 1999 Rev Ed), it no longer relies on those terms. ⁶⁵

31 For breach of the structural performance and fire safety requirements, Kalzip seeks a total of S$14,040,957.64 from BFG, comprising: ⁶⁶

(a) reimbursement for MBS’ deductions from the contract sum under the Trade Contract with Kalzip (S$8,685,495.74);

(b) the costs of investigating and developing remedial solutions for the defective GRP panels (S$476,969.78);

(c) the costs of implementing safety measures until a remedial solution for the defective GRP panels could be implemented (S$433,880.10);

(d) the costs of storing the GRP panels intended for installation on the theatre building roof from January 2010 to April 2011 while a remedial solution was developed (S$323,842.32);

(e) prolongation costs for a total period of 134 days (S$642,633.00);

(f) costs incurred as a result of MBS’ call on the performance bond under the Trade Contract with Kalzip (S$32,649.25);

(g) Kalzip’s advisory legal costs prior to the arbitration proceedings against MBS (S$1,328,130.55); and

(h) the costs of the arbitration proceedings against MBS, less the S$1.5m in costs that the arbitral tribunal ordered MBS to pay Kalzip (S$2,117,356.90).

32 Further and/or in the alternative, Kalzip claims S$4,874,319.45 in restitution for the return of monies it paid to BFG under the Sub-Contract on the basis of total failure of consideration. It alleges that BFG completely failed to supply panels which complied with the requirements of the Sub-Contract, were fit for purpose under the Sub-Contract and/or were accepted by MBS for use in the Project. ⁶⁷

33 The issues that fall to be decided are as follows: ⁶⁸

(a) What were the structural and loading requirements under the Sub-Contract, and did the GRP panels comply with those requirements? In particular:

(i) Do the structural tests establish that the GRP panels breached the structural and loading requirements of the Sub-Contract?

(ii) Did the GRP panels supplied to the Project exhibit delamination of the inner skin from the honeycomb core? If so, what was the cause of delamination?

(b) Did the GRP panels supplied to the Project meet the fire safety requirements of the Sub-Contract?

(c) Did the GRP panels breach the implied terms set out at [29] above?

34 Kalzip also invites the court to decide on BFG’s liability in principle in contract for each of the heads of claim enumerated at [31] above, as well as BFG’s liability in restitution. ⁶⁹ BFG contends that the issue of its liability in restitution should be left to the quantum stage of the trial ⁷⁰ , although its closing submissions canvass its arguments on this issue in full. I will therefore have to decide whether BFG’s liability in principle should be determined at this stage, and if so, whether it is liable under the express or implied terms of the Sub-Contract and/or in restitution for the panels supplied.

35 As this is a judgment of some length, I set out a brief table of how I deal with the various issues:

36 Kalzip called the following five factual witnesses: ⁷¹

(a) Mr Alan Roy Bridger (“Mr Bridger”), Kalzip’s Managing Director for 11 years (1998–2009), then Head of Business Development of Tata Steel (2010 to the present);

(b) Mr Stuart Mackay (“Mr Mackay”), Kalzip’s Project Manager for the Project from August 2009 to July 2011, who left Kalzip’s employ in June 2015;

(c) Mr Wong Kee Lou (“Mr Wong”), Kalzip’s System Design Engineer for the Project from 29 September 2008 to 4 July 2011, who continues to be employed by Kalzip as a Technical Sales Manager;

(d) Dr Jürgen Neuwald (“Dr Neuwald”), the director of Kalzip’s holding company, Kalzip Business Unit, from 2003 to 2011; and

(e) Mr Frank Guenter Mueller (“Mr Mueller”), the head of Group Legal and Compliance (Germany) in Tata Steel, who became involved in the Project in June 2010 when he was informed about the alleged delamination.

37 BFG called the following six factual witnesses: ⁷²

(a) Mr Suhas Kolhatkar (“Mr Kolhatkar”), the engineer in charge of the design of the GRP panels and the proprietor of Indian firm Composite Designs & Technology (“CD&T”), which enjoys a long-standing working relationship with BFG;

(b) Mr Krishnamoorthy Premamoorthy (“Mr Premamoorthy”), who managed the factory where the GRP panels were produced and has been Vice President of the Philippines branch of BFG since 1997;

(c) Mr Clive Lee Attwood (“Mr Attwood”), who was employed by BFG in 2000 and appointed BFG’s Project Manager of the Project from early April 2009 to 30 March 2010;

(d) Mr Kevin Grantly Flook (“Mr Flook”), the Group Business Director of BFG since February 2010;

(e) Mr Sanjay Rade (“Mr Rade”), the design engineer and assistant to Mr Kolhatkar at CD&T; and

(f) Mr Zeeyad Abdul Sattar (“Mr Zeeyad”), appointed as BFG’s Quality Assurance Manager for the Project sometime in 2008.

38 Except where I have expressly stated below, I did not find any of the factual witnesses to be particularly evasive or unforthcoming. It is not uncommon for people to form a preliminary view of the facts which, over time, becomes entrenched, leading them to conclusions which may not be entirely accurate or which may not comport entirely with the evidence. The witnesses’ views about delamination in this case may have been especially prone to this sort of entrenchment because of the dearth of unambiguous primary evidence. Nevertheless, I did not (except where expressly stated) consider them to be dishonest or biased, and accepted that they were for the most part attempting to recollect what had occurred to the best of their ability.

39 Kalzip and BFG each called one structural expert, one GRP expert and one fire expert, as follows: ⁷³

40 BFG’s structural expert was Mr Wymond, the founder and managing director of the Inhabit Group of companies. ⁷⁴ He had limited experience in the use of GRP as a building material. His previous experiences with GRP had not involved an aluminium honeycomb core, and had not involved the use of GRP in large flat cladding elements. ⁷⁵ His expertise lay in the mechanical properties and structural issues relating to GRP, whereas Mr Maurieschat’s expertise lay in material-related issues concerning GRP. ⁷⁶

41 Mr Maurieschat has headed the micro production and application process working group at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM (“Fraunhofer IFAM”) since 2008. ⁷⁷ However, he did not have any experience working with aluminium honeycomb GRP panels for use in buildings. He had only worked with such panels for building car bodies for the railway industry. ⁷⁸

42 Kalzip’s structural expert was Mr Green, who holds a degree in mathematical physics from Birmingham University and has spent his entire working life in the window, cladding and curtain walling industry. ⁷⁹ Mr Green stated that he did not profess to be an expert on any aspect of fibreglass skinned aluminium honeycomb panels, as that was Prof Nonhoff’s realm. ⁸⁰ He had also never worked with a product that combined aluminium with fibreglass-reinforced plastic. ⁸¹

43 Prof Nonhoff has been a Professor Emeritus of structural mechanics, aircraft construction and fibre-reinforced plastics at the University of Applied Sciences Aachen in Germany since 1973. ⁸²

44 In assessing the reliability of the expert evidence given by the experts before me, I found Mr Wymond’s expert evidence more helpful in forming my conclusions in this Suit. His evidence was generally consistent, well-reasoned and usually supported by calculations where appropriate. Mr Green made a few errors in his report (see in particular [54] and [77] below), though he was willing to recognise and admit these errors as well as the limitations of his expertise ⁸³ , and came across as an honest witness.

45 As between Mr Maurieschat and Prof Nonhoff, I found Mr Maurieschat’s evidence to be more persuasive. He came across as a forthcoming and neutral witness and was careful about the conclusions which he felt able to draw from his experience and the evidence. While Prof Nonhoff may have had more extensive experience with GRP panels in the past, and was the only one amongst the four experts who had come into contact with the actual panels in this Suit (having been invited onsite in 2010), I had difficulty accepting some aspects of his evidence and placed the least reliance on his evidence. His evidence on the presence and extent of delamination, unlike most experts, was general in nature. He did not mark out and could not identify which panels had “sounds” and which had deformed or deflected underfoot. He did not take a single photograph, besides photographs of samples which he had cored and of a panel which he had pulled apart by hand, to substantiate his observations and conclusions. As to the latter, there were no close-up photographs to substantiate his view. In particular, Prof Nonhoff claimed that he was able to see delamination on GRP panels which were kept in storage by spotting 1mm–2mm deformations on the reflective or shiny surface of the inner skin. I do not accept his evidence on this because, as I explain below, there are other photographs which show that the inner skin had a matted and slightly bumpy texture. This was also apparent from the core sample which was adduced in evidence. Such small deformations of that magnitude would therefore not have been noticeable. Moreover, the panels were packed so closely together in the stillages that it would have been very hard to examine them, save for the two outermost panels (see [244(c)] below). Indeed, when I asked Prof Nonhoff how wide the deformation had spread, he admitted that he could not see very far inside the stillage. ⁸⁴ I note, moreover, that Prof Nonhoff simply assumed the existence of delamination when he was first invited onsite, and his observations were perhaps for that reason not well-documented. This may be understandable given that he was invited onsite primarily to aid Kalzip in investigating and formulating remedial measures, rather than to determine whether delamination had in fact occurred. Nevertheless, the scarce primary evidence and lack of documentation with relevant details limited the assistance that I derived from his evidence.

46 It will be appropriate at this stage to briefly explain the composition of the GRP panels. The GRP panels are a type of fibre-reinforced plastic (“FRP”) composite product. FRP is composed of a polymer matrix reinforced with fibres. The polymer matrices can be of various resins whilst the fibres used are usually glass or carbon. GRP is a common type of FRP. ⁸⁵ As indicated above, the GRP panels had a sandwich construction. The top and bottom surfaces of each panel, referred to as the “skins”, were fire-retardant and made of glass fibre reinforcements and a polyester resin. The top surface was additionally coated with an off white polyester gelcoat for finish. The two skins sandwiched a layer of aluminium honeycomb with a 19mm cell size. ⁸⁶ The skins were bonded to the honeycomb with resin. The outer (top) and inner (bottom) skins also extended past the edge of the honeycomb and joined at the ends to form a U-shaped seal or U-channel, thereby forming a complete and seamless envelope around the aluminium honeycomb. This can be seen from the diagram on the right:

47 The panels measured about 3m wide and 10–14m long. ⁸⁷ The honeycomb aluminium came in sheets of 0.5m by 3m, which were laid in the same orientation as the panel (ie, with their long sides parallel to the long sides of the panel). At every 500mm juncture along the width of the panel, a strip of chopped strand mat (a “Z-strip”) would be laid under one aluminium honeycomb sheet and across the top of the adjacent sheet using the same bonding resin mixture, so as to further strengthen the panel and join the outer and inner skins together. Given that the aluminium honeycomb sheets were 0.5m wide, and the GRP panels were 3m wide, there would have been five Z-strips running through the length of each roof panel. Because the Z-strips were made of the same substance as the inner and outer skins, it fused with them, and the two skins were directly and strongly bonded at the location of each Z-strip. An actual core sample from one of the MICE building panels which had a Z-strip running through it was tendered in evidence. By attempting to pry the inner skin away from the honeycomb, I observed that adhesion between the inner and outer skins and the aluminium honeycomb was much stronger at the location of the Z-strip and that the Z-strip prevented the sample from being pried apart.

48 According to the Sub-Contract, the panels were to be 22mm thick with a manufacturing tolerance of +/- 1mm. ⁸⁸ BFG pleads that the parties had mutually agreed that the thickness of the GRP panel would be changed from 22mm to 24mm. ⁸⁹ This appears to be based on correspondence between the parties in November 2008 in which BFG informed Kalzip that the panels’ minimum thickness was 22mm but their maximum thickness was 24mm, and the drawings showed 24mm as a “space envelope dimension”. ⁹⁰ In any event, whether the panels were 22mm or 24mm thick has no bearing on the issues in dispute.

49 Three types of panels were manufactured for the Project: roof panels, fascia panels and return panels. The roof panels were to be installed horizontally (ie, lying atop the roof) while the fascia panels and return panels, which were generally smaller than the roof panels, were to be installed vertically. ⁹¹ Kalzip puts the number of manufactured panels at 3,421. ⁹² According to the site survey plans, there were 350 roof panels on the casino building, 467 roof panels on the MICE building and 296 panels on the theatre building. ⁹³ The process by which they were manufactured is described in detail at [316] below.

50 The loading requirements of the panels were described in terms of four types of load:

(a) dead load (the panel’s own weight);

(b) live load (a temporary load produced during, for example, maintenance by workers, equipment or materials);

(c) maintenance load (similar to a live load, and periodically applied during and as a result of maintenance activities such as cleaning); and

(d) wind load (the forces arising from the impact of the wind). ⁹⁴

51 Annexure 2 of the Sub-Contract states: ⁹⁵

52 Specification Revision C reiterated the same loading requirements in respect of the live load and maintenance load, but gave a different wind load requirement: ⁹⁶

53 In requiring a “Live Load 0.75kPa”, the Sub-Contract required the GRP panels to be capable of bearing a uniformly distributed load of 0.75 kilopascals (“kPa”). This was equivalent to 75kg spread evenly over a surface area of 1m2. ⁹⁷ As for a maintenance load of 1.1 kilonewtons (“kN”), this required the GRP panels to be capable of bearing a point load of 110kg over a circular area 150mm in diameter. The experts agreed that the reference to “150 mm2” in Specification Revision C was a mistake, as that would require a maintenance load of 110kg to be borne by an area approximately the size of a postage stamp; the requirement, as correctly stated in Annexure 2, was for that load to be borne by a circular area 150mm in diameter. ⁹⁸

54 In terms of wind load, Annexure 2 of the Sub-Contract required the GRP panels to bear a positive wind load resistance of 1.25 kPa (equivalent to a force of 125kg per m2 of the panel) and a negative wind load (ie, suction) of 2 kPa. ⁹⁹ However, para 2.1.6 of Specification Revision C required the wind load requirements to be calculated from CP3 Chapter V, Part 2, ie, the chapter on “Loading”, specifically “Wind loads”, in the British Standards Institution’s Code of Basic Data for the Design of Buildings. ¹⁰⁰ Mr Wymond criticises these specifications, on the basis that best building practice requires buildings with a complex form to be wind tunnel tested. ¹⁰¹ Nevertheless, they were contractually agreed. Although Mr Green initially took the view that the negative wind load ought to be 2.25 kPa ¹⁰² , based on his calculation of wind load requirements in CP3 Chapter V, he conceded during trial that he had made a mistake in the calculation. He had based his calculations on a pressure coefficient table within CP3 Chapter V setting out “Pressure coefficients Cph/wL/w which took account of “the combined effect of the wind on both upper and lower surfaces of the canopy for all wind directions”. ¹⁰³ However, in actual fact, the GRP panels lay atop a Kalzip sheet, such that the GRP panels only received wind pressure on their top surface and not from wind travelling underneath them. Mr Green was therefore wrong to treat the GRP panels as canopy roofs, and this mistake led him to overstate the design wind load in the original calculations. ¹⁰⁴ He was thus content to accept that -2.0 kPa was the correct figure for the design wind load. ¹⁰⁵

55 The parties were in disagreement over what was the “CPP Wind Load Report” referred to in para 2.1.6 of Specification Revision C. Kalzip identifies it as a report issued by Cermak Peterka Petersen (“CPP”) on 9 February 2009. ¹⁰⁶ However, BFG points out that this report is dated nearly six months after the date of the Purchase Order and cannot have been the report referred to. In any case, this dispute is academic because the parties agree that the wind load requirements were +1.25 kPa and -2.0 kPa. ¹⁰⁷ I note also that Mr Green calculated the positive wind load under CP3 Chapter V as +1.4 kPa. ¹⁰⁸ However, Mr Wymond did not comment on this in his report and I say no more about this given the parties’ agreement on the wind load requirements. ¹⁰⁹

56 As for the deflection limits, para 2.2.3 of Specification Revision C stated: ¹¹⁰

57 “L” refers to the measurement of the span between supports. Annexure 2 of the Sub-Contract provided that Kalzip would provide “continuous supports to GRP panels at every 1500 mm in length direction and at every 800 mm in the width direction of the panels as installed”. As the distance between supports was 1500mm, the maximum allowed deflection would be 8.33mm (1500mm divided by 180). ¹¹¹

58 However, this deflection limit was relaxed because Kalzip agreed to purchase panels made to specifications which it knew would have breached the deflection limit of 8.33mm. This appears to have been due to financial considerations. On 21 May 2008, BFG sent Kalzip a price table showing the prices for panels made to various specifications, including: ¹¹²

(a) a 15mm-thick panel with a 500mm-by-400mm support grid (S$140/m2 CIF Singapore; S$131/m2 ex-works BFG Bahrain/Philippines);

(b) a 22mm-thick panel with a 750mm-by-800mm support grid (S$135/m2 CIF Singapore; S$126/m2 ex-works BFG Bahrain/Philippines); and

(c) a 28mm-thick panel with a 1000mm-by-800mm support grid ($185/m2 CIF Singapore; S$176/m2 ex-works BFG Bahrain/Philippines).

59 The 22mm-thick panel was thus the cheapest of the three options. BFG subsequently revised its price table to provide for a support spacing of 1500mm by 800mm, which would substantially reduce the cost of the Kalzip support rail structure. ¹¹³ On 20 June 2008, BFG e-mailed Kalzip a deflection table stating the deflection limits of GRP panels of different thicknesses and support grid spans. ¹¹⁴ The deflection table, titled “Podium Roof GRP Deflection Matrix Summary_A_20Jun08.pdf” (“the BFG Deflection Table”), was incorporated by Annexure 1 to the Purchase Order. ¹¹⁵ It set out the following deflection limits for 22mm-thick GRP panels with grid spacing across width of 1500mm and length of 800mm: ¹¹⁶

60 The BFG Deflection Table expressly stated that a 22mm-thick GRP panel with 1500mm grid spacing across width and 800mm grid spacing across length was “Not Recommended as the wind suction deflection is excessive”; this was written in red. Another two sets of specifications were annotated with the following remarks in red respectively: “Rejected. Stresses exceed limiting value under wind suction” and “Not recommended as the point load deflection is excessive”. In contrast, three other specifications were annotated with “Acceptable limits” in green font and three others with “Could be considered with relaxed Deflection limits” in blue font. Kalzip presented this information to MBS on 26 June 2008 but deleted BFG’s column of remarks and instead colour-coded the deflections. ¹¹⁷ , and amber to indicate “>l/180 and >15mm but less than l/50”. Mr Bridger explained that removing BFG’s remarks and presenting the information using a colour legend was meant to make it “more visual” for MBS. ¹¹⁸ I do not accept this explanation. In my view, this was prone to mislead the reader of that document. The colour-coded table, unlike BFG’s remarks column, did not properly convey that the deflections shaded in amber exceeded the deflection limit stated in para 2.2.3 of Specification Revision C. But whatever the case, MBS chose those specifications, and Kalzip therefore contracted to purchase 22mm-thick GRP panels from BFG at S$135/m2 and install them on a 1500mm-by-800mm span grid. ¹¹⁹ There is no question that Kalzip was aware that this configuration would only have a maximum deflection limit of 29mm, and that this relaxed limit was incorporated into the Sub-Contract.

61 The structural experts agreed that the deflection criterion at maximum wind uplift was relaxed either to L/100 or 29mm, but did not know which. ¹²⁰ As the distance between supports was 1500mm, L/100 = 15mm. ¹²¹ If it was the lesser of these which applied, then the deflection limit would be 15mm, but if not, then the more generous limit of 29mm would apply.

62 BFG submits that the deflection limit of the GRP panels under a load of -2.0 kPa was 29mm. ¹²² Kalzip has not taken a position on whether the deflection limit was 29mm or 15mm. The question may be largely academic given the experts’ unqualified agreement that delaminated panels would have breached the deflection limits (see [99] below). Mr Green also said at trial that delaminated panels would have breached even the relaxed criterion of 29mm ¹²³ and I note that Mr Wymond did not contradict him. However, the question of which was the correct limit does have some relevance to the structural test conducted on 24 September 2010, where the deflections recorded were between 15mm and 29mm (see [96] below). Insofar as the deflection limit carries consequences for the analysis, I prefer BFG’s position for the following reasons:

(a) This question concerns the terms of the Sub-Contract. While the experts’ views are helpful to me in understanding the technical issues, they cannot be definitive in construing the terms of the contract. In my view, the contractual documents support a relaxed limit of 29mm. Annexure 1 to the Purchase Order expressly incorporates the BFG Deflection Table as “part of this purchase order”. It also states unequivocally, “All expected deflections based on the table submitted by BFG using FEA in BFG’s mail dated 20th June 2008 under document reference 2 [ie, the BFG Deflection Table].” ¹²⁴ That table clearly states a limit of 29mm at the design negative wind load.

(b) Kalzip’s account of MBS’ choice of the panels also shows that the agreed deflection limit was 29mm. Its closing submissions state: ¹²⁵

(c) Indeed, Mr Flook’s affidavit of evidence-in-chief (“AEIC”) confirms that “the panels originally selected by MBS have a ‘Span/ 51 limit’” (ie, 29mm), whereas Kalzip requested replacement GRP panels in August 2010 with a different deflection limit of Span/100 (ie, 15mm). This explains Mr Kolhatkar’s e-mail to Mr Carter on 4 August 2010, attaching the BFG Deflection Table, which stated that “The panels selected by MBS are having Span / 51 limit.” ¹²⁶ Other e-mails subsequently exchanged between Kalzip and BFG discussed two different prices, one for replacement panels which would be manufactured to comply with the existing deflection limit, and one for replacement panels which would conform to a stricter limit of L/100 and thus be more expensive. ¹²⁷

(d) By contrast, there is no mention of L/100 in the deflection table or, as far as I am aware, any other contractual documents. BFG’s reply submissions therefore assert that “Kalzip has not explained how and why the deflection limit ought to be ‘L/100’ even though this is not stated in the Sub-Contract nor the documents referenced in the Sub-Contract”. ¹²⁸ Counsel for Kalzip had an opportunity to address this in oral submissions over a month later but did not do so. ¹²⁹

(e) Kalzip’s experts, Mr Green and Prof Nonhoff, testified at trial that if there was a deflection of up to 29mm, the GRP panel would still be within the contract specifications. Mr Wymond also agreed that the panels would have complied with the relaxed deflection criteria if they deflected up to 29mm. ¹³⁰

63 I also note that some experts (for example, Prof Nonhoff ¹³¹ ) were queried about whether other standards would have been more appropriate than Specification Revision C for the Sub-Contract. However, that is irrelevant to the issue at hand: Specification Revision C was chosen by the parties and defines the contractual obligations which the parties undertook to fulfil towards each other.

64 Various structural tests were performed on the GRP panels in 2008–2010. Some were conducted by BFG and some by Winwall Technology Pte Ltd (“Winwall”). Although Kalzip pleaded reliance on the Winwall tests in its Statement of Claim, it now expressly disavows reliance on those tests as evidence of breach of the structural performance requirements. ¹³² However, even if Kalzip were to rely on those tests, I do not think they would advance Kalzip’s case. For completeness, and because some time was spent on these tests at trial, I set out my views on these tests at [75]–[97] below. This also carries consequences for other parts of the analysis. For example, the tests form part of the basis of Prof Nonhoff’s view regarding the delamination ¹³³ as well as the basis of a non-conformance report issued by Aedas on 17 May 2010, which Kalzip does rely on. Moreover, though Kalzip does not rely on these tests “as evidence of breach of the structural performance requirements”, the tests may still have relevance in the context of the cause of delamination or quantification of damages.

65 Mr Green and Mr Wymond both agreed that BFG’s test methodology was unreliable. Mr Green explained that the samples used by BFG were very small compared to the production panels and the support conditions did not replicate how they were to be supported in practice. ¹³⁴ The experts’ list of agreed points stated: ¹³⁵

66 However, they disagreed on the weight to be placed on the Winwall tests. While Mr Green accepted that the Winwall tests “were an improvement over the BFG tests”, he thought they were unreliable ¹³⁶ because they “still did not properly replicate the boundary conditions”. ¹³⁷ For example, the support rail failed two tests conducted by Winwall in April and May 2009 due to rotation, because the support rail had been asymmetrically loaded on one side only instead of two sides. In practice, each rail would have supported a pair of panels, which would have balanced out the forces acting on the rail and prevented rotation. Those test results were therefore not representative of how the support rail system functioned in practice. ¹³⁸ The BFG and Winwall tests therefore could not be reliably adopted as a gauge of whether the GRP panels would have met the deflection limits of the Sub-Contract. ¹³⁹

67 Mr Wymond, on the other hand, agreed that the BFG testing was rudimentary but thought that the Winwall testing showed very important information notwithstanding “some evidence of rail rotation during testing owing to asymmetric loading on the rail cross-section”. ¹⁴⁰ The rotation did not mean that the Winwall test was totally irrelevant, for the following reasons:

(a) First, there were 86 edge panels in the design of the building, and the rails supporting these edge panels would have been subjected to asymmetrical loading. ¹⁴¹ However, drawings of the upper roof of the casino building showed that these edge panels were anchored at their ends, which was not the configuration when the panels were tested. ¹⁴²

(b) Secondly, Mr Wymond pointed out that some panels were narrower than others. While most were 3m wide, some were only 0.7m wide. ¹⁴³ It was therefore possible for a rail to support a full width panel on one side and a much smaller panel on the other side. The load on one side of the rail could be roughly double that on the other side. ¹⁴⁴ Mr Green agreed that this seemed logical. However, while he accepted it was possible for the rail to be eccentrically loaded where an edge panel was anchored at the end or where it supported two differently sized panels, it would not be as eccentric as it was under the Winwall testing conditions. ¹⁴⁵

(c) Thirdly, asymmetrical loading could also occur for a rail which supported one panel in a high wind load zone adjacent to another panel in a lower wind load zone. ¹⁴⁶ Mr Green agreed that this was possible, though he thought that any differential in wind load would be very minor. ¹⁴⁷

68 Notwithstanding that he considered the Winwall tests to be of some value, Mr Wymond acknowledged that they did not test the performance of the GRP panels in isolation. He stated: ¹⁴⁸

69 This reduces the utility of the Winwall tests, because BFG’s contractual responsibility was limited to ensuring that the panels met the Sub-Contract requirements provided they had “continuous supports … at every 1500mm in length direction and at every 800 mm in the width direction of panels as installed”. BFG was not responsible for designing or installing the supporting structure. The Sub-Contract stated that the “assessment of capacity of the entire support structure” was “out of BFG’s scope” and it did not have to “ensure the safety & adequacy of supports in terms of reactions from the Cladding”. ¹⁴⁹ In fact, Mr Wymond took the view that the panels deflected excessively in the Winwall tests only because of rail deflection and rotation, rather than because of any deficiency in the panels themselves. For example, he noted that bracket disengagement was a problem in the test on 14 and 15 July 2009. ¹⁵⁰ I now turn to the individual tests.

70 BFG refers to two static load tests that it carried out on 29 September and 24 November 2008. ¹⁵¹

71 On 29 September, two load conditions were simulated on a 1m-by-3m panel. It was made to bear first an imposed load of 1.25 kPa (corresponding to the wind load requirement, see [54] above). That load was then removed and the panel made to bear a “man load” of 1.1 kN in the form of a person weighing more than 100kg standing on the panel at pre-determined locations and walking on it. ¹⁵² The panel did not show any cracks or delamination following these tests. Nobody from Kalzip or MBS was present at this test. ¹⁵³ Because of the lack of third-party certification, this test was repeated on 24 November 2008 (see [73] below). ¹⁵⁴

72 In Mr Green’s view, this test was of “questionable” accuracy because a measuring point was shown in the geometric centre of the panel, which was no longer accessible once the sandbags used to impose the 1.25 kPa load were in place. Moreover, the photographs appeared to show a support at the mid span of the panel and the deflections were clearly visible. In any event, panel performance did not appear to be satisfactory because deflections of 8mm were recorded under a load of 220kg; the limit of L/180 in the case of a 1m metre panel would be 5.55mm. ¹⁵⁵ (Mr Green’s expert report states that the panel deflected up to 9mm under a load of 220kg. ¹⁵⁶ However, the test results show a deflection of 8mm at this load and a deflection of 9mm at a full load of 386kg. ¹⁵⁷ ) Moreover, given that both experts criticised BFG’s testing methodology (see [65] above), I place little weight on these test results.

73 The test on 29 September 2008 was repeated on 24 November 2008 so that it could be certified by a third party, TUV Middle East. ¹⁵⁸ This time round, the “man load” was imposed by having a person stand on the panel and increasing his weight to 112kg by having him hold small sand bags. He then walked on the panel and deflections were recorded. ¹⁵⁹ No cracking sounds were heard during or after testing and the panel remained intact. ¹⁶⁰

74 However, the test on 24 November 2008 was also unreliable because deflections were recorded around the quarter-points of the panel, instead of at the mid span, where deflection would probably have been greater. ¹⁶¹ Mr Green and Mr Wymond both agreed that tests by BFG on 29 September and 24 November 2008 were inconclusive. ¹⁶²

75 On 14 and 15 July, Winwall performed a structural test comprising (1) a cycle pressure structural test; (2) a structural test at serviceability limit state; and (3) a pull out test of the aluminium clip. ¹⁶³ The test panel passed the first two tests but the screws fixing the seam clip to the aluminium rail detached at -3 kPa. ¹⁶⁴ However, Mr Wymond pointed out that this failure was due to disengagement of the supporting brackets (ie, a component provided by Kalzip) rather than failure of the GRP panel itself. ¹⁶⁵

76 Kalzip’s witnesses, Mr Wong (who attended the test) and Mr Bridger, understood that the GRP panel had passed these tests. ¹⁶⁶ Mr Green originally took the view that the panel had deflected excessively during the tests on 14 and 15 July 2009. Under a negative wind pressure of 2.25 kPa, the panel’s deflections ranged from 15.21mm to 51.63mm. Mr Green had prepared his first expert report on the basis that the deflection limit was 15mm rather than 29mm ¹⁶⁷ (see [61] above); if this was correct, it would mean that the test panel exceeded the deflection limit at every measurement location. Under a positive wind pressure of 1.25 kPa, the panel deflected as much as 25.89mm, which would have exceeded a deflection limit of 15mm but not of 29mm. ¹⁶⁸

77 It turned out that Mr Green’s analysis of the 14 and 15 July 2009 test results were not only based on the wrong deflection limit (15mm), but also a misinterpretation of the test results. He originally asserted that the panel deflections recorded ranged from 15.21mm to 51.63mm. These figures represented the deflections recorded on two particular displacement transducers on the test specimen, as recorded in a table in the test report titled “A.2-3 Structural Test at Serviceability State (Negative Pressure)”. ¹⁶⁹ However, Mr Green conceded during trial that he ought instead to have taken the figures in Table 5.2, “Structural Test at Serviceability Limit State”, which calculated the deflection of the GRP panel based on mid-span displacement minus the average of the corresponding two end values. ¹⁷⁰ This table recorded the deflections at a maximum negative wind load of -2.25 kPa as ranging from -5.68mm to -12.87mm, which were within the deflection limit. The maximum deflection recorded at +1.25 kPa was 8.31mm. This led Mr Green to revise his opinion and conclude that the panel had in fact passed the test. Mr Green acknowledged that he had made a mistake and that his analysis of the underlying test data was very poor. ¹⁷¹ I also note that Mr Green initially took the view that the maximum wind suction under the Sub-Contract was -2.25 kPa, but during trial conceded that it was -2.20 kPa (see [54] above). In Mr Wymond’s view, a study of the deflections recorded by individual transducers showed that “the GRP-HC panel was stiff” and deflected in a similar way predicted by the finite element analysis. ¹⁷² I therefore do not accept the tests on 14 and 15 July 2009 as evidence that the GRP panels supplied by BFG failed the structural performance requirements under the Sub-Contract.

78 Winwall conducted a cycle pressure structural test and a structural performance test on 29 and 30 April 2010 respectively. ¹⁷³ An e-mail from Arup Façade Engineering (“Arup”) records that “[c]rackling noise[s]” were heard and became louder as the pressure was increased, until bangs were heard “when the pressure was reaching towards ~2000/2250 Pa” and a couple of areas towards the central area and towards one side of the panel “lifted up”. At this point the test was stopped. ¹⁷⁴ As a result, the panels did not even undergo the more stringent proof load test at the ultimate limit state. ¹⁷⁵

79 According to Arup, failure occurred during the design load negative pressure test. However, this was premised on the assumption that the design load negative pressure was -2.25 kPa, ¹⁷⁶ whereas I have explained at [54] above that the wind load requirement was actually -2.0 kPa. Although the panel failed at “~2000/2250 Pa”, according to Mr Wong, after applying an area reduction factor, the equivalent of 2.25 kPa suction was a test load of 2.067 kPa. This meant that the test panel did in fact withstand the design suction load, since the test failure occurred only at a test load of 2.20 kPa. ¹⁷⁷

80 Moreover, the failure appears to be attributable to failure of the supporting components. Mr Rade’s report of the test records that at a load of 2.2 kPa, “the aluminium support structure failed at one of the side[s]” and that the “flanges of the aluminum rail, where z-cleats were engaged, were buckled excessively under suction”. This “resulted [in] the delamination of the ferrule from panel” and in “excessive deflection in GRP panel”. The report states that because the sliding Z-clips disengaged, the entire load became concentrated on the location of the fixed Z-clips, causing the ferrule to debond at that location; “[i]n short, the test mock of support structure failed to provide the structural support to GRP panels”. ¹⁷⁸ A set of photographs taken of the April 2010 tests showed aluminium rail failure due to bending, sub-rail connection failure, rotation of the Z-clips and significant deflection of the panels. ¹⁷⁹ Mr Wong agreed on the basis of these photographs that the support rails had rotated during the test. ¹⁸⁰ This is corroborated by an e-mail sent by Mr Carter on 3 May 2010, which stated, “Report on the nature of failure - it is presumed that the structural failure occurred due to excessive rigidity being introduced into the test rig build up”. ¹⁸¹ I therefore accept BFG’s submission ¹⁸² that the tests carried out on 29 and 30 April 2010 do not prove that the GRP panels failed to satisfy the structural loading and/or deflection requirements of the Sub-Contract.

81 On 14 May 2010, Winwall performed a test on a panel measuring 3.53m by 11.7m, originally destined for the theatre building roof. This involved using air pressure to simulate wind loading on the panel. The panel performed satisfactorily in the cyclic pressure and positive pressure tests, but the rail and Z-clips along one side of the panel disengaged due to the support rail undergoing excessive rotation during the negative pressure test at a negative pressure of -2.067 kPa. ¹⁸³ At that point, panel deflections had already exceeded 15mm. The test report issued by Winwall states in relation to the negative pressure test, “Excessive displacement along entire length of GRP panel, about 500 mm from one side of GRP panel was noted during application of negative pressure. Excessive deflection caused the panel to rupture at -2067 Pa. Test stopped.” ¹⁸⁴

82 Mr Wymond considered that the GRP panel failed the test not because it was inherently inadequate but because of design faults in the aluminium support system. ¹⁸⁵ In support of this he referred to screenshots taken from videos of the 14 May 2010 test. ¹⁸⁶ Mr Wymond thought these screenshots showed that the angle between the horizontal flange and the vertical wall of the support rail had widened after load testing. ¹⁸⁷ If he was right, this would be evidence of rail bending and deformation. Mr Green, on the other hand, thought that the rail had merely rotated without bending or deforming. ¹⁸⁸ I agree with Mr Wymond; a close study of the two screenshots shows that the angle between the vertical wall of the rail and the horizontal flange had widened.

83 BFG rightly points out that the pressure at which the panel ruptured, -2.067 kPa, exceeded the design wind load of -2 kPa. At -2.067 kPa, the highest deflection was recorded as 28.68mm, which was still below the deflection limit of 29mm. ¹⁸⁹ (Although BFG reads this deflection as 28.88mm, the test report appears to state 28.68mm, but this is inconsequential for present purposes. ¹⁹⁰ ) Moreover, a report prepared by BFG on the 14 May 2010 test explains that after applying a reduction factor, 2067 Pa was equivalent to 2.25 kPa of suction. ¹⁹¹

84 BFG attributed the failure of the April and May 2010 tests to the other test components rather than the GRP panels themselves. Its report states: ¹⁹²

85 The same explanation was repeated in an e-mail from Mr Flook to Mr Carter on 17 May 2010; he said that it was “evident from the video” of the 14 May 2010 test that the movement of the panels had to be restricted by having a fully rigid rail structure. Mr Flook also pointed out that the rail structure in the test was unevenly loaded, and that even loading might bring stability to the rail structure in practice. ¹⁹³

86 Kalzip appeared to accept that the test failed because the Kalzip support rail had rotated, not because the GRP panels were structurally inadequate. This is evident from a GRP status report sent by Mr Carter to MBS on 4 June 2010: ¹⁹⁴

87 In BFG’s submission, Mr Carter’s e-mail related to the April and May 2010 tests and showed that the failures occurred because the support rail system designed for the test did not really reflect actual site conditions. ¹⁹⁵ There was no problem with the GRP panels themselves. Although Mr Wong disagreed with Mr Carter’s e-mail, he accepted that the test set-up was not identical to the site condition. He disagreed primarily because he felt that the test set-up, although not identical to the site condition, had been approved by Arup and was the best that could be done. ¹⁹⁶ Be that as it may, the question is whether the test – however it was conducted – is evidence that the GRP panels breached the structural requirements of the Sub-Contract. Having considered the evidence, I find that it did not.

88 Winwall conducted another test on 17 June 2010 on another uninstalled theatre panel. It was subjected to a cycle pressure structural test, a structural test at serviceability limit state (to +1.25 kPa and -1.15 kPa) and an ultimate load test (to +1.875 kPa and -1.725 kPa). ¹⁹⁷ At a negative pressure of -1.15 kPa, large deformation was recorded in the centre of the panel which exceeded the maximum measuring capacity of the linear transducers. The largest recorded figure was 36.72mm at a positive pressure of 1.25 kPa. ¹⁹⁸ It appears that Transducers 15 and 19 malfunctioned, ¹⁹⁹ but even disregarding the deflection of 36.72mm recorded by Transducer 19, the next highest deflection would be 34.11mm (recorded by Transducer 10). The panel withstood the positive pressure of 1.875 kPa for 10 seconds without any rupture or visible failure of any component. However, it ruptured after being subjected to a negative pressure of 1.725 kPa for eight seconds, at which point a screw also became detached and an aluminium support bracket began to bend. ²⁰⁰

89 After the negative pressure test, photographs were taken showing a screw detached from a bracket, a bent bracket, and a portion of the GRP panel which had ruptured. ²⁰¹ These were, again, components of the support system provided by Kalzip. Mr Rade, who witnessed this test, recalled that there were no signs of any structural failure of the test panel, although the fixation screw between one of the fixed brackets and aluminium rail had snapped out. ²⁰² Mr Wymond noted that, as with previous tests, “the mock-up failed at the junction between the Z Clips and the rails with a screw coming out, rail flange bending and the prying of a z clip out of the GRP-HC panel”. ²⁰³ I therefore agree with BFG that this test does not prove that the GRP panels failed to comply with the structural loading and/or deflection requirements of the Sub-Contract. ²⁰⁴

90 Winwall was commissioned by BFG to conduct a pressure test on 8 September 2010, which involved using air pressure to simulate wind loading on a large panel measuring 2.98m by 10.27m originally meant to be installed on the theatre building roof. ²⁰⁵ The panel was subjected to a cycle pressure structural test and to a structural test with loads of up to +1.25 kPa and -2.25 kPa. In order to test the performance of the panels in isolation, and avoid failure of the support structure, the test panels were mounted on a rigid steel support structure. ²⁰⁶ The panel performed satisfactorily under a positive pressure of 1.25 kPa. However, at -2.25 kPa (which was equivalent to a load of -2.475 kPa given the area of the test chamber), the specimen withstood the load for one minute but the bolts fixing the aluminium fixed clips to the GRP panel detached at two locations. ²⁰⁷

91 Mr Green and Prof Nonhoff emphasised that the panel “had additional fixings and a different method of support and resulted in the pulling out of the cast in ferrules to which the Z clip is fixed”. ²⁰⁸ Similarly, Prof Nonhoff said that the panel had “additional external fixings”, and agreed with Arup’s analysis that the test therefore did not give any indication as to whether the panels would withstand the design wind pressures without remedial measures. ²⁰⁹

92 Mr Green pointed out that under a negative pressure of 2.25 kPa, structural failure occurred “in the form of detachment of the aluminium fixing clips”. ²¹⁰ BFG takes this to mean that it was the aluminium clip supplied by Kalzip that failed, and not the GRP panel. ²¹¹ It was also Mr Wymond’s view that the test failed because no measures had been taken to prevent the Z-clips from rotating and causing the ferrules to bend. ²¹² (In any event, the maximum suction under the Sub-Contract was -2.0 kPa, not -2.25 kPa: see [54] above.)

93 However, Mr Green also observed that deflections were measured as high as 36.99mm at a negative pressure of 2.25 kPa, and he considered the high residual deformations recorded within the test results as evidence of failure. ²¹³ BFG disputes that the deflections were this high. It hypothesises that Mr Green adopted this figure from a table in the test report stating the deflection recorded by one particular transducer (Transducer 1), whereas the deflection ought to have been calculated based on the mid-span displacement minus the average of the corresponding two end values (which, in the case of Transducer 1, was 4.94mm only). ²¹⁴ Unfortunately this was not put to Mr Green during the trial. Nevertheless, this appears to be the exact same error which Mr Green acknowledged he had made in relation to the tests on 14 and 15 July (see [77] above) and the Winwall test report is clear that the deflection limits were not exceeded. I therefore do not accept Mr Green’s evidence that the 8 September 2010 test showed that the GRP panels deflected excessively, much less that they deflected excessively at design load. I find that this test also does not show that the GRP panels breached the structural requirements of the Sub-Contract.

94 Winwall performed another test on 24 September 2010, which involved using air pressure to simulate wind loading on a large panel measuring 2.98m by 11.5m. ²¹⁵ The panel was subjected to a structural test at serviceability limit state and an ultimate load test. The latter involved applying negative step pressures to the test panel, the greatest being a pressure of 3.25 kPa for one minute. ²¹⁶ Under positive wind load pressures up to 1.25 kPa, the maximum deflection recorded was 17.97mm. Under negative wind load pressures of up to 2.25 kPa, the maximum deflection recorded was 21.75mm (recorded at a wind load of -1.15 kPa). ²¹⁷ At a negative pressure of 3 kPa, the panel started to rupture and made cracking noises. (According to Mr Wong, this meant that the panel failed at -3 kPa. ²¹⁸ ) It was observed that the panel bulged upwards, several aluminium clips along the middle railing detached, a portion of the aluminium railing bent at the middle of the specimen, and the aluminium railing at the sides of the specimen tilted. ²¹⁹

95 Prof Nonhoff thought that this test showed that there was a problem with the manufacturing of the GRP panels, because the panel ruptured and bulged upwards during the ultimate load test. ²²⁰ However, the pressure of -3 kPa far exceeded the design pressure under the Sub-Contract. The panel’s performance at that pressure is not indicative of its compliance with the structural requirements of the Sub-Contract. Moreover, as Mr Wymond observed, the Winwall test report highlighted a failure of the rails and clips and it is not known whether the rails and clips caused the panel failure or vice versa. ²²¹ I accept Mr Wymond’s view. In this respect I find Prof Nonhoff’s views rather partial.

96 Mr Green considered that the deflections recorded showed the structural inadequacy of the GRP panels. However, as with his comments on the 14 and 15 July 2009 tests, Mr Green had based this analysis on a deflection limit of 15mm. He thus considered that the largest recorded deflections – 17.97mm and 21.75mm at pressures of +1.25 kPa and -1.15 kPa respectively – exceeded the “maximum allowable deflection limit of 15mm”. ²²² These were, however, well within a relaxed limit of 29mm (see [62] above).

97 BFG submits that the test specimen was not representative of an actual GRP panel because holes were cored along the sides of the test panel, filled with resin and cured prior to the test. ²²³ Mr Wong agreed that the test panel was therefore different from the panels installed on site. ²²⁴ However, as Mr Wong pointed out, the holes were cored so that screws could be put in to fix the panels to the support rail. This was done on Mr Carter’s instructions to improve the support conditions, so that the test results would be improved. ²²⁵ BFG did not adduce any evidence or explanation why the presence of the holes would have impaired panel performance. In any event, the deflections were, in my view, within the deflection limit of 29mm.

98 Given my finding that the Winwall tests do not show that the panels failed to meet the structural performance requirements in the Sub-Contract, and bearing in mind that Kalzip does not rely on them to establish its case (see [64] above), I turn to the question of delamination. Unless Kalzip is able to prove that the panels delaminated due to defective manufacturing, it will have failed to establish that BFG breached the terms of the Sub-Contract.

99 Importantly, the experts agreed that “[i]f the panels had delaminated they would not have satisfied the deflection criteria”. Mr Green clarified at trial that delaminated panels would have breached even the relaxed criterion of 29mm. ²²⁶ This was shown by a set of tests commissioned by Mr Wymond and Mr Maurieschat and conducted by Kaskal Façade Testing Centre (“Kaskal”) and Fraunhofer IFAM on 17 and 18 August and 14 September 2015 (“the 2015 Tests”). I elaborate on these tests in greater detail at [183] below. In Mr Green’s view, the tests from August 2015 showed that delaminated panels deflected more than non-delaminated panels; the panels with “floating” inner skins failed the deflection criteria under negative pressure. ²²⁷ With the inner skin detached, the test panel deflected up to 59.26mm, strongly suggesting that if the panels had delaminated in 2009 or 2010, they would not have met the deflection criteria set out in Specification Revision C. ²²⁸ Kalzip therefore takes the position that delaminated GRP panels would not have satisfied the deflection criteria of the Sub-Contract, and that the question of BFG’s compliance with the requirements of the Sub-Contract can be determined by investigating whether the GRP panels had in fact delaminated. ²²⁹

100 BFG takes a contrary view to that of the experts. It submits that “the structural experts’ opinion that the deflection criteria would not be satisfied [if delamination occurred] is not in fact tested and/or supported by any test results – it is based on an entirely theoretical assumption that can never occur on site”. ²³⁰ Although the panels with “floating” inner skins may have failed the deflection criteria under the Sub-Contract, the actual GRP panels installed for the Project would not have completely delaminated due to the presence of Z-strips at 500mm intervals. ²³¹ Moreover, no tests were conducted on actual delaminated panels from the Project to see how much they deflected. ²³² I also note that some of BFG’s witnesses referred to documents which suggested that even delaminated panels would have met the Sub-Contract Requirements. For example, Mr Kolhatkar referred to a document titled “MBS_Analysis of Delaminated panel_11march10” which allegedly demonstrated that panels with a “floating bottom skin” nevertheless had sufficient residual strength to resist stresses specified in the Sub-Contract, ²³³ as well as to a report by BFG dated 23 March 2010 which suggested that a delaminated panel would deflect only up to 16.14 or 15mm. ²³⁴ However, these documents were not put to the expert witnesses or referred to in BFG’s closing submissions, leading me to conclude that they did not play any significant role in BFG’s case.

101 I accept the experts’ evidence that delaminated panels would not have met the Sub-Contract requirements, for the following reasons:

(a) Both Mr Wymond and Mr Green agreed that delaminated panels would have failed the deflection criteria under the Sub-Contract. They both also confirmed this view at trial. ²³⁵ Significantly, their agreement on this point was not confined to a panel that had delaminated fully, even though they were both aware that the 2015 Tests had been conducted on totally delaminated panels (and in fact Mr Wymond directed and attended the tests on 17 and 18 August 2015). ²³⁶ There was no reason for me to disagree with their expert opinion. If BFG had reasons for disagreeing with the experts’ conclusion, it ought to have probed and tested their evidence on this issue at trial, but did not do so.

(b) During the 2015 Tests, the test panels with delaminated inner skins deflected up to 59.26mm. This was very much higher than the contractual deflection limit of 29mm. Even if BFG is right that the GRP panels installed onsite would not have delaminated totally, and would therefore have deflected less, the deflection in the 2015 Tests was so excessive that I have little difficulty accepting the experts’ view that delaminated panels would likely have failed the deflection limit of 29mm.

(c) BFG refers to the opinion expressed by Kalzip’s wind-loading expert in the arbitration, Dr-Ing Rolf-Dieter Lieb, that “even in a delaminated state, the majority of the panels could meet the actual wind loads. There were only a small number of GRP panels in highly loaded areas which could not meet the wind loads”. ²³⁷ However, even in Dr Lieb’s opinion, some panels would (if delaminated) have been unable to bear the actual wind loads. Furthermore, these “actual wind loads” do not appear to have been the wind loads specified by the Sub-Contract – they were “significantly lower than those that applied to the closed building envelope (as had been specified in Revision C)”. ²³⁸ In any event, since Dr Lieb is not a witness in the Suit and was not present to explain or defend his view, I do not take his opinion into account.

102 It follows that I must determine the issue of whether delamination occurred onsite. As I have already noted above, unfortunately, the panels which were actually installed in the Project were removed and had been discarded by the time of the hearing. There is no primary evidence of what condition the panels were in at the time they were removed. ²³⁹ As noted earlier, there are also no photographs showing a panel with a delaminated skin. Although the panels were removed, no tests were conducted on them nor were they preserved to show that they had delaminated. None of the panels that had yet to be installed on the theatre roof were retained for the purpose of proving that there was inner skin delamination in this Suit, even though Kalzip sent some of these for testing by Winwall and could have preserved others or at least photographed those panels they claimed had suffered delamination.

103 Kalzip’s case is that “extensive delamination of the GRP panels was observed”. ²⁴⁰ It relies on the following evidence in support of its contention that the panels had delaminated: ²⁴¹

(a) internal communications within BFG from January to March 2010, showing its acknowledgement and acceptance that the GRP panels produced for the Project had delaminated;

(b) the evidence given by BFG’s witnesses of fact at trial, reinforcing that BFG accepted that the GRP panels produced for the Project had delaminated;

(c) site surveys carried out jointly by Kalzip, BFG and MBS between February and March 2010, which allegedly identified and located delaminated panels onsite;

(d) evidence that MBS’ consultants, Aedas Pte Ltd (“Aedas”) and Arup, concluded that the GRP panels on the casino and MICE building roofs had delaminated; and

(e) BFG’s provision to Kalzip of a draft proposed remedial solution on 21 January 2011, which was also consistent with its acknowledgement of the existence of delaminated GRP panels onsite.

104 First, I deal with BFG’s preliminary point that Kalzip has only pleaded reliance on four site surveys in support of its case on delamination. ²⁴² These were surveys that Kalzip commissioned and carried out to identify delaminated GRP panels on site. The four survey diagrams – two of the casino roof, dated 6 and 25 February 2010, and two of the MICE roof, dated 2 and 8 March 2010 – were essentially site plans of the panels installed on each building, annotated in yellow to show areas which had allegedly delaminated. ²⁴³

105 The fact that Kalzip only pleaded reliance on four site surveys does not, on the facts and circumstances of this case, preclude reliance on other evidence to establish its case. Order 18 r 7 of the Rules of Court (Cap 322, R 5, 2014 Rev Ed) only requires the parties to plead “a statement in a summary form of the material facts on which the party pleading relies for his claim or defence … but not the evidence by which those facts are to be proved”. As stated in Singapore Civil Procedure 2017 vol 1 (Foo Chee Hock JC gen ed) (Sweet & Maxwell, 2017) at para 18/7/10:

106 Material facts refer to “all the facts which constitute a cause of action or defence so that [the party] will be in a position to offer evidence of them at trial”. Where an action is brought for breach of contract, the material facts will include the existence of the contract, its nature (whether it was oral or verbal or by deed, express or implied), the terms alleged to have been breached, the nature of the breach and the loss and damage sustained as a result of the breach (Jeffrey Pinsler, Singapore Court Practice 2017 vol 2 (LexisNexis, 2017) at pp 696 and 698).

107 Kalzip has pleaded the alleged facts crucial to its claim, including that the panels exhibited delamination of the lower face sheet from the honeycomb core of the GRP panels, and that this delamination impaired the panels’ load-bearing behaviour, rendering them non-compliant with the loading and structural performance requirements of the Sub-Contract. ²⁴⁴ Kalzip did not need to plead the correspondence between the parties and the various observations of its witnesses during site inspections, since these merely constituted the evidence supporting its allegation of delamination.

108 Having said that, I should point out that, especially in building and construction cases of this nature, which involve detailed facts and technical issues, it would be good practice to plead with greater specificity so as not to take the other side by surprise. As the discovery progressed here, I note that BFG did not ask Kalzip if it was going to rely on anything other than the surveys to prove delamination of the inner skins. That would have been the correct course to take if BFG had wanted Kalzip to nail its colours to the mast. However, in this case, given the evidence put forward by both sides, no prejudice was caused as each party knew what it had to meet.

109 On the facts and circumstances of this case, I may therefore have regard to all the evidence relied upon by Kalzip. The evidence, taken together, paints a coherent picture of the state of affairs between the parties in 2009 and 2010. They agreed that the GRP panels had delaminated. This was borne out by correspondence within BFG internally, between BFG and Kalzip, and reports from MBS’ consultants Arup and Aedas. However, BFG’s case is that this consensus was based on an erroneous assumption that certain noises which the panels emitted when walked upon were indicative of delamination. In the next two subsections I explain how the issue of delamination arose and set out the site surveys and correspondence which Kalzip relies on as evidence of the same.

110 I first address two factory visits which were conducted on 3 September 2008 and 23 April 2009. I note that Kalzip is clearly not relying on the events of either visit as proof of delamination, ²⁴⁵ and will here explain why it is in my view unable to do so.

111 First, there was an inspection of BFG’s factory on 3 September 2008. According to Mr Bridger, who was not present, defects involving delamination of the GRP panels became evident during the inspection and the panels were subjected to a “‘live load’ (foot traffic) test”. ²⁴⁶ A report produced by Arup and Aedas records that when Mr Jan Oebeles walked along the panel, a “cracking” sound was heard by all present. The conclusion of the test was that: ²⁴⁷

112 This test spawned concerned e-mails from Mr Carter (Kalzip’s project director), who informed BFG’s Mr Kolhatkar that there was “extensive panel deformation and delamination of the 22mm panel” apparently due to “insufficient resin cover across the honeycomb”, and from Kalzip’s Mr Michael Moloney (“Mr Moloney”), who added that the 22mm-thick panel “cracks & moans (loadly) [sic] when you walk on it, giving evidence to the de-lamination of the resin from honeycomb”. ²⁴⁸ The “moans” was clearly an exaggeration as no one else described such a sound.

113 I accept Mr Kolhatkar’s explanation on this point. He explained that the samples used for this test had been provided primarily for visual purposes and for fitout and joinery testing, rather than for live load testing. They had not been made using the intended reinforcements and resin, as these items had not yet been ordered, and had not undergone a vacuum bagging process due to lack of time. ²⁴⁹ Moreover, the test had involved manually tearing apart the sample, “as a result [of which] the inner GRP layer delaminated from the aluminium honeycomb with the honeycomb still attached to the outer GRP layer”. This, in Mr Kolhatkar’s view, was the wrong way to test for delamination as an actual panel would not have to undergo that type of force. ²⁵⁰ He disagreed that a properly bonded panel would be able to withstand such a tear test and therefore did not consider this test as evidence of delamination of the GRP panels. ²⁵¹

114 I note that Mr Premamoorthy gave evidence in his AEIC that he would “typically carry out tap testing as well as try to physically pull apart the skins of open edge sample panels to determine if there is adequate adhesion”. ²⁵² In his view, it should not be possible to pull the skin apart from the aluminium honeycomb by hand if there was proper adhesion between them. ²⁵³ However, Mr Premamoorthy made that remark in the context of his discussion of the process development phase, ie, the phase of trying to develop a process for the manufacture of the GRP panels. He did not say that it was a scientific method of determining whether a panel had delaminated; it was, rather, a means of testing the strength of the adhesion between the skins and the honeycomb core. Mr Kolhatkar explained that a tear test would result in delamination if “the force exerted exceeds the resin strength of the honeycomb of any core with the skin laminates”. If one were to try pulling the skins apart by hand, different people would exert different forces. The more appropriate test would be to apply a load to the panels and measure the pull-out strength by reference to the stresses induced. Mr Kolhatkar disagreed with counsel’s suggestion that “where you have a properly laminated, properly bonded panel, you should be able to retain the bonding when you do such a tear test”. ²⁵⁴ Indeed, the expert evidence supported Mr Kolhatkar’s statement that a tear test was not necessarily indicative of a delamination problem. Prof Nonhoff’s and Mr Wymond’s expert opinion was that it was possible to peel the inner skin off a panel by hand (see [244(d)] below). Prof Nonhoff and Mr Maurieschat also agreed that the bonding at the edges of an intact GRP panel would have made the panel stronger at those edges, and therefore harder to pull apart. ²⁵⁵

115 Leaving the 3 September 2008 inspection to one side, Mr Kolhatkar claimed that he observed a problem of debonding during other trials on the GRP panels around September 2008. ²⁵⁶ That he considered delamination to be a problem is evident from his e-mail to the process engineer from BFG’s headquarters in Bahrain, Mr Ananthanarayanan Venkateswaran (referred to in the proceedings as “Mr Anand”) on 26 September 2008, titled “Podium Roof ALHC Bondi[n]g problem”: ²⁵⁷

116 “Delimitation” appears to have been a typographical error; it should have been “delamination”. Mr Kolhatkar also agreed during cross-examination that he was “seriously concerned about … the back skin delamination problem”. ²⁵⁸ However, this correspondence occurred during the process development phase of the project, when the process of manufacturing the panels was still being finalised.

117 The next event which Kalzip refers to in its closing submissions is a factory visit on 23 April 2009. ²⁵⁹ Representatives of MBS, Aedas, Arup, Moshe Safdie Architectural (“MSA”) and BFG attended an inspection at the BFG production facility in the Philippines. During the visit, Mr Carter stood on one of the sample fascia panels to test its structural strength. According to Mr Bridger, who does not appear to have attended the inspection, the panel “exhibited excessive deflection characteristics with audible cracking and it was apparent that the lower face sheet was delaminating” when Mr Carter stood on it. ²⁶⁰ Mr Attwood and Mr Premamoorthy, who attended the inspection, both gave evidence that Mr Carter not only stood but jumped on the panel. I pause to note that under cross-examination, it was put to Mr Premamoorthy by counsel for Kalzip that it could not be true that Mr Carter jumped on the panel because if that had happened he would have put it in writing, and Mr Premamoorthy agreed. ²⁶¹ However, that answer was, in my assessment, a result of my intervention as I tried to clarify for him what a “put” question meant. Prior to that, he was quite adamant that Mr Carter had jumped on the panel. During the visit, BFG was requested to cut samples from a large panel to be taken away and this was done. ²⁶² Arup produced a report labelled “BFG Philippines GRP Panel Inspection (TC3215) - No. 2” dated May 2009 (“the May 2009 report”). Under the section titled “Honeycomb Construction”, the report stated: ²⁶³

118 As with the 3 September 2008 inspection, Kalzip expressly eschews reliance on the 23 April 2009 factory inspection as proof of delamination. ²⁶⁴ In my view it does so rightly, because the observations of delamination do not appear to be reliable. First, Mr Attwood gave evidence that he and others from BFG had objected to cutting the samples from a panel because such samples would definitely have been damaged by the very process of cutting, but did so anyway on MBS’ insistence. ²⁶⁵ Kalzip makes the point that Mr Attwood made this objection as a non-expert and was not technically trained to make the observation that jumping would damage the panel. ²⁶⁶ However, this criticism rings hollow given that Kalzip itself mentions Mr Attwood’s 30-odd years of experience in the composites industry in relying on his assessment that delamination had occurred. ²⁶⁷ The objection was reiterated in an e-mail sent by Mr Kolhatkar to Mr Moloney on 27 April 2009, in which he stated, “On a properly cured panel in regular production cycle, there is no delamination of back layer … What you have seen was unproperly cut piece not from a regular production panel. … [T]he actual production panels have a direct connection between top and bottom layers with a layer of glass every 500 mm.” ²⁶⁸ This is also supported by expert evidence from Mr Wymond, who states that the “peel resistance of aluminium honeycomb is very low due to a very small contact area being subjected to a highly concentrated load”, and so peeling a cut sample is not a realistic test of delamination. ²⁶⁹ The reference to a “direct connection” every 500mm was a reference to the Z-strips. I have explained, at [47] above, that the Z-strips bonded the inner and outer skins directly and helped to fortify the panels against delamination.

119 Secondly, Mr Attwood also gave evidence that, during the inspection, he objected to Mr Carter standing and jumping on the panel on the basis that the GRP panels had been designed only to withstand the loads specified in the Sub-Contract. ²⁷⁰ Mr Attwood’s criticisms are echoed by Mr Premamoorthy. He explained that the test panel had been prepared merely for visual inspection and was placed on a random material handling frame. The panel was not supported with a proper support frame and the span of the support was approximately 4–5m, compared with the panel’s span of 0.5m. Nor was the frame affixed to the panel. As a fascia panel, it was meant to be installed in a vertical position onsite and would not have been walked upon (although Mr Premamoorthy did not say that fascia panels were manufactured differently or to different specifications than the roof panels, which were to be installed horizontally). ²⁷¹ I also find that jumping on the panel would have imposed a load in excess of the Sub-Contract requirements (see [306] below).

120 On the other hand, Kalzip refers to an e-mail from Mr Kolhatkar to Mr Anand on 10 May 2009 as evidence that BFG acknowledged that it faced a problem of delamination at that point in time. ²⁷² The e-mail stated, “At this stage the inter layer debonding is a serious concern, so is the client concern for back side ALHC to back skin debonding.” ²⁷³ [emphasis added] However, Mr Kolhatkar explained during cross-examination that the first matter (inter laminar delamination, or delamination within one of the skins), which is not in issue here, concerned him, but the second issue (delamination of the inner skin or back skin) was a “client concern which [he] conveyed back to Anand” and not something which seriously concerned him personally. ²⁷⁴ I accept his account, which is supported by another e-mail which he sent to Mr Carter on 8 July 2009, copying BFG’s Mr Attwood and Kalzip’s Mr Robert Talbot. In this e-mail Mr Kolhatkar attempted to assuage concerns of delamination arising from the May 2009 report. ²⁷⁵ He stated: ²⁷⁶

121 During cross-examination, Mr Kolhatkar explained that these cut panels were not representative of actual GRP panels because they lacked the U-channel edge detail which intact GRP panels would have had, and they had been subjected to cutting tools that could have induced vibrations in the panel, causing the inner skin to separate. ²⁷⁷ Moreover, the panels had not delaminated when they were cut; they only delaminated when they were pried apart. He therefore did not consider the tests on 3 September 2008 or 23 April 2009 as evidence of delamination of the GRP panels. ²⁷⁸ I therefore find that Kalzip was correct to abandon reliance on the factory visits on 3 September 2008 and 23 April 2009. However, these two factory visits caused Mr Carter, who appears to have a strong and assertive personality, to form the view that “cracking” noises in the panels evidenced delamination of the inner skins. He subsequently told BFG, as recorded in an e-mail from Mr Kolhatkar to Dr Samer on 8 February 2010, that what started off as a “metallic crinkling noise” in the panels would “eventually [result] in a de-bonding”. ²⁷⁹

122 Putting the two factory inspections to one side, Kalzip relies on subsequent site surveys and correspondence from BFG in 2009 and 2010 to show that BFG came to accept that there was delamination and it was a problem. While I set these out in some detail below, I should first caveat this section by saying that the correspondence can only show so much. The question in this suit, in view of BFG’s claim that it mistakenly confused the noises coming from the panels with delamination, is not merely whether BFG thought there was delamination, but whether it was right to think so or mistaken at the time in thinking so. The experts themselves disagreed on important questions such as whether the noises produced by the panels were evidence that they had delaminated, and whether inner skin delamination on localised areas could be visually observed. If some of the experts could have erred on these questions, then BFG, which had not manufactured panels of this type in such large sizes before, could have similarly made an erroneous assumption. BFG’s assertion that it was mistaken that the panels were defective therefore has to be carefully evaluated.

123 On 26 May 2009, during the process development phase and before the panels began to be manufactured ²⁸⁰ , Mr Rade e-mailed Mr Attwood saying: ²⁸¹

124 Counsel for Kalzip referred to this e-mail as evidence that delamination of the lower skin was a recognised problem at this stage. However, Mr Kolhatkar interpreted this e-mail as a caution that delamination would be a problem if the panel were subjected to loads (ie, the cylic loading test) which were not specified in the specifications previously given to BFG. ²⁸² This e-mail was generated before GRP panel production began.

125  The next e-mail, dated 7 December 2009, was written after panels had begun to be installed on site. Mr Attwood e-mailed Mr Kolhatkar, Mr Premamoorthy and others. The e-mail subject was “delamination of panels on site” and the body contained the following text: ²⁸³

Mr Attwood agreed during cross-examination that he was not reporting complaints or allegations by Kalzip, but giving his own observations of what had occurred onsite. ²⁸⁴ However, there was no examination of Mr Attwood on what exactly he had observed onsite to come to this view.

126 Sometime in early January 2010, when Mr Mackay was carrying out a morning inspection of the GRP panels on the casino building with MBS’ Project Manager of Facades Mr Jan Oebeles, Mr Mackay heard a cracking sound while traversing some of the panels. He notified Mr Carter of this after the inspection. The two of them then went onto the casino building roof and again noticed various panels producing a cracking noise underfoot. ²⁸⁵ Mr Mackay described this incident during trial as follows: ²⁸⁶

127 On 11 January 2010, Mr Attwood e-mailed Mr Kolhatkar, Mr Premamoorthy and Mr Zeeyad amongst others. The e-mail was titled “Delaminated Panels On site” and stated: ²⁸⁷

128 When this e-mail was brought to Mr Attwood’s attention during cross-examination, his answer was that he had simply used the word “delamination” because it was “common parlance at the time on site for what was perceived to be happening with [the] panels” and that he was, at the time, unsure of what was in fact wrong with the panels. ²⁸⁸ The six areas had been identified based on the presence of crunching sounds. ²⁸⁹ I have noted above at [111], [112] and [121] that at the factory visit on 3 September 2008, Kalzip and MBS’ consultants who were present formed the view that the “cracking” sound was indicative of delamination of the inner skin. It should also be noted that the e-mail above appears to describe delamination of the outer skin (“between front top face and aluminium honeycomb”), whereas Kalzip’s claim is for delamination of the inner skin. ²⁹⁰

129 On 18 January 2010, Mr Attwood emailed Mr Premamoorthy, Mr Kolhatkar, Mr Zeeyad and others. The subject of the e-mail was “Damaged crates and panels @ Toll Singapore”. It included the following: ²⁹¹

130 In another e-mail about an hour later, Mr Attwood stated that the debonding issue “appears to be on the top surface but there [is] no way of saying 100% that this is the case with out [sic] cutting”. ²⁹² When Mr Anand replied to ask how many panels were affected, Mr Attwood replied six panels. ²⁹³

131 Again on 18 January 2010, Mr Attwood wrote to Mr Mackay (copying Mr Carter and Mr Kolhatkar) that: ²⁹⁴

132 Mr Carter replied on the same day, stating, “Following receipt of the plastic and plywood (Have you considered structural foam), [Kalzip] will arrange for this to be installed.” ²⁹⁵ Notably, Mr Carter did not deny that the panels were being walked on, or that the walking had damaged the panels. Rather, he simply assured Mr Attwood that Kalzip would arrange for plywood to be installed. This suggests that Mr Carter – who was described by other witnesses as aggressive, and who comes across in the correspondence as assertive and not easily persuaded to change his mind – accepted the possibility of damage to the panels as a result of foot traffic.

133 On 20 January 2010, Mr Attwood e-mailed Mr Carter, Mr Kolhatkar, Mr Premamoorthy, Mr Zeeyad and others, stating: ²⁹⁶

134 As noted above, this probably referred to the same six panels at [127]–[128] above, which were described as experiencing outer skin and not inner skin delamination. Mr Attwood agreed that this e-mail showed that he and BFG had concluded, after a site inspection by BFG (probably done by Mr Attwood and Mr Anand or Mr Rade), that six panels had delaminated. ²⁹⁷ Mr Attwood agreed that BFG reached that conclusion independently of Kalzip and on the advice of Mr Attwood and a product expert (whom Mr Attwood thought would have been either Mr Anand or Mr Rade). ²⁹⁸ I have also noted that in his 18 January 2010 e-mail (see [130] above), Mr Attwood did say that debonding “appears” on the top surface and that the only way to say this was the case was by “cutting” into the panel.

135 On 21 January 2010, Mr Kolhatkar e-mailed Mr Carter regarding the delamination. He wrote: ²⁹⁹

136 This “draft methodology” involved drilling an 11mm-diameter hole into an area of the panel experiencing delamination and funnelling resin into the honeycomb, which would then drip through the honeycomb and fill the delaminated gap. ³⁰⁰ Mr Kolhatkar did not accept during cross-examination that this repair methodology was evidence that delamination had in fact occurred; it was, rather, a response to a “perceived problem” which had been reported back to him by his BFG team onsite.

137 On 26 January 2010, Mr Attwood and others went on another site visit. At a progress meeting that day, which Mr Carter attended, the minutes of meeting noted: “MBS advised that beside panel 13 on Casino leaf 13, 2 more panels are found damaged …”. ³⁰¹ I note that this only refers to “damaged” and not “delaminated” panels.

138 On 27 January 2010, Mr Attwood emailed Mr Premamoorthy, Mr Kolhatkar, Mr Zeeyad and others. The e-mail subject was “MICE furher [sic] delaminated panels” and it stated, “After walk through yesterday there are in total 20no delaminated panels on Mice random throughout the panel area and this is after just being installed. [T]here is talk that these panels will be condemned”. ³⁰² During trial, Mr Attwood explained that he had referred to “delaminated panels” as panels exhibiting a crunching sound when walked upon. As he was not a technical expert, he had assumed that these sounds were evidence of delamination. ³⁰³ These were panels which had just been installed, which meant that any delamination which had occurred by that point was not attributable to foot traffic. ³⁰⁴

139 On 27 January 2010, Mr Attwood again emailed Mr Premamoorthy, Mr Kolhatkar, Mr Zeeyad and others stating: “Out [of] 70 odd panels (Shipments 1 and 2) installed so far on MICE 20 have delamination which is in areas limited to less than 1 [square metre] at a time. … So far in whole of casino there are a further 8 panels.” Mr Attwood stated that the MICE panels were not delaminated when they left the factory and considered it unlikely that they had delaminated during travel or from being stepped on after installation. He theorised that the way in which they were lifted or handled was over-stressing parts of the panel which were less strongly bonded, thus causing the delamination. ³⁰⁵ During cross-examination, Mr Attwood denied that BFG had independently arrived at the conclusions stated in the e-mail ³⁰⁶ , even though he had earlier agreed that BFG had independently arrived at the conclusion stated in his e-mail of 20 January 2010 (see [134] above). Notably, the e-mail shows that BFG was undecided about the cause of the reported delamination and took the view that the panels had left the factory intact and without delamination.

140 On 29 January 2010, Mr Kolhatkar e-mailed Dr Samer Al Jishi (the managing director of BFG) (“Dr Samer”) with an “update on the site issues with MBS panels”. He stated: ³⁰⁷

141 I note that this e-mail captured what had been “reported” to Mr Kolhatkar. In other words, Mr Kolhatkar was not giving Dr Samer his own view of what had occurred onsite, but merely relating what he had been told. Mr Kolhatkar also suggested various hypotheses: for example, that the panels had deformed as a result of being subjected to excessive loads, and that there was in fact no delamination but only the impression of delamination as a result of the sounds being made by the panels when walked on. Importantly, he told Dr Samer that Kalzip was unable to show Mr Premamoorthy an actual instance of delamination when he was onsite.

142 On 30 January 2010, Mr Kolhatkar e-mailed Mr Premamoorthy and Mr Attwood and wrote, “It is apparent that CASINO panels do have real delamination. On MICE Panels there is ALHC sound.” ³⁰⁸ When asked in cross-examination why he did not reply to this e-mail to correct Mr Kolhatkar, Mr Attwood responded that he had not had time to send an e-mail. ³⁰⁹ This was of course untrue as he had replied that very day, attaching a Quicktime video of the sounds heard when the MICE panels were walked on, which he described as “pretty wide spread in the areas being walked on” and “much less so on the areas that aren’t”. ³¹⁰

143 Also on 30 January 2010, Mr Attwood e-mailed Mr Kolhatkar, Mr Premamoorthy and Mr Anand. The subject of this e-mail was “panel that is spongy on casino” and the text of the e-mail stated, “this is on bay 10, there are others [despite] us telling them to cove[r] with ply it is not panel has sunk it is as most of the delamination is in the area where there is roped access”. ³¹¹ Mr Attwood explained that the subject of his e-mail referred to the sensation of the panel deflecting downwards as he stepped on it. ³¹² According to Mr Attwood, this was the only panel he saw which exhibited such sagging. ³¹³ During cross-examination, Mr Kolhatkar accepted that the photograph attached to the e-mail showed that the panel was sagging. ³¹⁴

144 On 31 January 2010, Mr Attwood sent an e-mail to other persons from BFG saying, “can we please check that we are not producing panels that have crunchy aluminium in them as has been seen on site in Singapore”. ³¹⁵

145 On 1 February 2010, a team attended an inspection of the MICE and casino buildings. In his AEIC, Mr Rade stated that he attended this inspection along with a number of Kalzip personnel, including Mr Carter and Mr Charles Leong (“Mr Leong”), and a few other workmen. He recalled that Mr Attwood and Mr Anand also attended. Mr Rade’s purpose in attending the inspection was to inspect the panels and identify if there were any structural defects (including, potentially, delamination) associated with a metallic crunching sound that had been heard emanating from the panels. ³¹⁶ During that survey, Kalzip workmen walked and/or jumped on the panels looking for crunching sounds. They appeared to associate the crunching sounds with delamination. Mr Carter also instructed a team of about eight to ten people to stand in a line across the entire width of a selected panel and walk up and down the panel at the same time to detect crunching sounds. Mr Rade recollected that some of the people jumped on the panels. ³¹⁷ He considered this method of attempting to detect delamination to be “completely incorrect” because the alleged delamination had occurred between the aluminium honeycomb and the inner skin, and would therefore have to be detected from below, not above. ³¹⁸ The correct method, in his view, would be to remove the panel and inspect the inner skin. ³¹⁹ Mr Rade stated at trial (though this was not in his affidavit) that he had raised this objection to Mr Carter and Mr Kolhatkar but to no avail. ³²⁰ Indeed, Mr Kolhatkar had expressed his view that metallic noises were not necessarily indicative of delamination in his e-mails to Dr Samer and Mr Carter on 29 January and 2 February 2010 (see [140] above and [147] below).

146 Following the 1 February 2010 inspection, Mr Attwood e-mailed Mr Kolhatkar, Mr Premamoorthy and others. The subject of the e-mail was “1st Feb report on site visit and debrief discussions on MBS panel defects”. The e-mail stated that there were two distinctly different types of problems onsite: ³²¹

Mr Attwood agreed, on the basis of this e-mail, that he was in fact reporting delamination on the casino panels. ³²² When asked why he did not object to this e-mail since he did not think that the crunching sound could be equivocated with delamination, Mr Rade said that he simply deferred to Mr Attwood’s observations since Mr Attwood was onsite for a much longer period and had inspected more of the roof. ³²³ Whatever the case, Mr Rade seems to have accepted delamination as a problem soon after (see [150] below).

147 On 2 February 2010, Mr Kolhatkar e-mailed Mr Carter to inform him of the preliminary observations of BFG’s inspection and assessment team onsite. These were as follows: ³²⁴

148 On 3 February 2010, a site investigation was conducted by Mr Carter, Mr Attwood, Mr Anand and Mr Rade. Their joint report, attached to Mr Kolhatkar’s e-mail to Dr Samer dated 8 February 2010, largely repeated the observations regarding the casino panels, but new delamination was observed on some of the MICE panels: ³²⁵

149 On 6 February 2010, a partial survey of the casino building roof was carried out. ³²⁶ This is the first of the four site surveys pleaded by Kalzip (see [104] above). According to Mr Mackay’s AEIC, the survey was undertaken by Mr Leong on Mr Carter’s instructions. The survey showed that 9% of the roof area “exhibited signs of sagging and emitted crackling sounds when walked upon”. ³²⁷ I pause to note that, while Mr Mackay maintained that the site surveys were based on both the cracking sounds and sagging or deflection underfoot, other witnesses claimed that the site surveys were based wholly on the sounds produced, and it is not clear which (if any) site surveys Mr Mackay attended (see [172]–[174] below). I therefore do not accept his interpretation of the site surveys as evidence of panels which emitted cracking sounds and deflected underfoot. None of Kalzip’s witnesses in this suit was able to say for sure that they had attended this site survey (see [174] below). Mr Attwood, however, gave the following evidence in his AEIC: ³²⁸

I note that this method is similar to Mr Rade’s recollection of what was done during the 1 February 2010 site inspection (see [145] above). I return to this site survey at [171] below.

150 On 8 February 2010, following a site inspection by a team of technical experts engaged by BFG, Mr Rade reported the findings of the inspection to Mr Kolhatkar, Mr Attwood and others by e-mail. He wrote: ³²⁹

151 This e-mail appeared to be inconsistent with Mr Rade’s evidence at trial that he had not personally observed any delamination as a result of the 1 February 2010 inspection (see [145] above). However, Mr Rade explained that Mr Attwood had by then already reported delamination, and BFG was in the process of devising a repair procedure. Mr Rade therefore apparently accepted Mr Attwood’s position that there was delamination, although he also pointed out in paragraph 2 that the “metallic cracking sound” did not necessarily indicate delamination. ³³⁰

152 On 11 February 2010, Mr Kolhatkar e-mailed Mr Attwood, copying Mr Anand, Mr Rade and others. His e-mail stated: ³³¹

153 Mr Attwood agreed on the basis of this e-mail and others that BFG personnel consistently recognised that delamination had occurred to the GRP panels on the casino building. ³³²

154 The second of the four site surveys pleaded by Kalzip was conducted on 25 February 2010. ³³³ According to Mr Mackay’s AEIC, Mr Leong carried out this survey. ³³⁴ Mr Attwood testified that he had attended and that Mr Rade and Mr Anand were also present. ³³⁵ According to Mr Mackay, the survey shows that 14% of the casino building roof surface area “exhibited signs of sagging and emitted crackling sounds when walked upon”. This appears to be his general understanding of the survey process as he does not profess to have attended this particular survey. ³³⁶ After this survey, Mr Attwood e-mailed Mr Kolhatkar and others from BFG attaching the marked-up site diagram. He wrote: “attached is the pic of survey completed yesterday on Casino orange areas show dela[m]inated panels 56 areas on 46 panels”. ³³⁷

155 Mr Attwood agreed that if he felt any hesitation about the conclusion that the survey showed delamination on 56 areas on 46 panels, he would have made that clear in his e-mail report. However, he also said he had by this time “begun to believe that the panels were delaminated” but “had not seen any evidence to that [effect]”. ³³⁸ He maintained that he had not seen any delamination during the site surveys. ³³⁹ I pause to note that there is no evidence at all during these surveys that anyone inspected the inner skins of any of these panels emitting sounds to confirm that there was inner skin delamination or that a panel was taken off and examined or tested to confirm the same.

156 There was another site inspection on or around 26 February 2010, although it did not result in a site diagram marked up in yellow unlike the other four site surveys. Mr Mackay and other representatives from MBS and BFG inspected the casino and MICE building roofs. Mr Mackay recalls that everyone who attended “observed that there were significant numbers of delaminated panels by walking on the panels to identify deep crunching noises”. ³⁴⁰ The assumption that deep crunching noises mean delamination is evident from this.

157 There was another site inspection on 2 March 2010 ³⁴¹ , as well as a core sampling exercise (which I expand on at [235] below). Mr Flook recalled attending the inspection and said that Mr Carter had walked and jumped on some panels to show that they were emitting crunching sounds, but Mr Flook himself “found it very difficult to hear any alleged crunching sounds”. ³⁴² Mr Attwood and Mr Flook also attended the core sampling exercise along with Mr Anand and possibly Mr Rade. ³⁴³ Mr Mackay also recalled attending the core sampling exercise, ³⁴⁴ during which he heard “cracking sounds” coming from the GRP panels on the MICE building roof and “[d]eep cracking noises” from the casino building roof ³⁴⁵ . According to Mr Mackay, the survey showed that almost all the installed GRP panels on the MICE building roof “exhibited signs of sagging and emitted crackling sounds when walked upon”. ³⁴⁶ This is clearly an exaggeration, because the site survey only shows about 113 panels marked in yellow. I note that not all the panels had been installed by this point, but even counting only those bays which had been fully installed and which had panels marked in yellow, only about half or just over half of the panels were marked as delaminated.

158 On 8 March 2010, Mr Leong conducted the fourth of the site surveys, on the MICE building roof. Mr Flook attended this survey and recounted that it was carried out in the same manner as the survey on 2 March 2010, ie, based on the crunching sounds heard when the panels were walked and jumped upon. ³⁴⁷ All the GRP panels had been installed by that point. The survey, ³⁴⁸ in Mr Mackay’s words, showed that nearly all the panels “exhibited signs of sagging and emitted cracking sounds when walked upon”. ³⁴⁹ Again, this was an exaggeration: just under half of the panels on the site survey (220 of about 467) were marked in yellow.

159 On 11 March 2010, Mr Premamoorthy e-mailed Dr Samer apparently attributing the delamination to the resin used and the choice of material. He stated: “My opinion is that the aluminum honeycomb and k133 Resin that we used. Aluminum will not bond well with GRP … In addition to that, whenever we use K133 Resin, we always ended up with problems.” ³⁵⁰ Dr Samer replied that same day, saying, “This incosistency [sic] cannot happen from a process problem and is more indicative of a manufacturing defect. Come on Moorthy, the delaminated skins are very dry …” ³⁵¹

160 Dr Neuwald also stated at trial (although this was not in his affidavit) that he had personally observed delamination during his site visits in June 2010. He was in the company of Prof Nonhoff on some of these occasions. ³⁵² When asked how he identified delamination, Dr Neuwald responded that “[y]ou can witness [delamination] by a number of aspects”, including that the panel was no longer stiff but softer or spongy and/or was emitting crunching sounds. ³⁵³ Unfortunately, he did not say which (if any) of these phenomena he in fact observed in June 2010 or how widespread these phenomena were, or identify which panels, in his view, had delaminated inner skins. I also note that Dr Neuwald’s evidence corroborates Prof Nonhoff’s account (see [208] below).

161 Kalzip’s expert, Mr Green, relied on these internal e-mails from BFG as evidence of delamination, as he had never seen the GRP panels or walked on them. ³⁵⁴ When asked what his view would be if he were told to disregard those e-mails, Mr Green said he would still hold his opinion that there was delamination on the basis of what he had “subsequently heard from the evidence of other people, including expert evidence from Professor Nonhoff”. ³⁵⁵

162 It may seem odd that there is no record of any delamination being visually observed. However, this does not necessarily mean that none occurred. The evidence suggested that the delamination would not be obvious to the naked eye. Prof Nonhoff said that the surface of the inner skin would be “a little bit shining” (which I understood to mean slightly reflective), which would make it easier to notice distortions and “loose areas”, allowing delamination to be seen very easily. ³⁵⁶ However, he appeared to recognise the need for “special training” in order to be able to determine if a panel had delaminated by examining it visually. ³⁵⁷ Mr Maurieschat went even further, disagreeing that delamination could be seen in the way that Prof Nonhoff suggested. He took the view that any delamination would be localised due to the presence of Z-strips every 500mm and would therefore not be of such large dimensions. Moreover, because of the stiffness of the inner skin, one would not see a “bubble” as a result of delamination. Delamination in a “little area” would not be visible. If, however the entire panel were to delaminate, then its surface would probably be noticeably curved. ³⁵⁸ I accept this evidence of Mr Maurieschat. Mr Wymond likewise thought that delamination would not have occurred over spans exceeding 500mm and that it was “unlikely” that somebody would be able to see delamination from the back of a panel. ³⁵⁹ While the surface was somewhat reflective, it was also broken up by Z-strips and joint lines from lapping layers, and was not smooth. ³⁶⁰ The absence of any visual identification is therefore not necessarily conclusive as to whether delamination had or had not occurred.

163 Kalzip relies heavily on BFG’s internal correspondence to support its case that delamination had occurred, whereas BFG submits that it did not in fact hold such a view but merely went along with Kalzip’s assertion that delamination had occurred.

164 First, Mr Attwood said that he had used the word “delamination” extensively in his communications with BFG because it was “very hard to disagree with [Kalzip] at that time, being very forceful, that delamination had occurred on the panels”, and that by “delamination” he had meant to denote the noises that were coming from the panels. ³⁶¹ Mr Attwood also insisted that he had used the word “delamination” because he had no evidence that it was not delamination, and he made certain judgments that he came to believe were wrong. With the benefit of hindsight, he realised that he did not know what was going on onsite. ³⁶² He stated that he lacked the technical depth to deal with issues relating to delamination. ³⁶³ However, he did not qualify any of his e-mails or observations of delamination with the caveat that he lacked technical expertise, nor did anyone his team ever suggest that he was out of his depth. ³⁶⁴ He also repudiated any suggestion that he had been intimidated into saying that delamination had occurred when it had not. ³⁶⁵ Having considered the totality of his evidence and his demeanour under cross-examination, I accept that Mr Attwood based his assertions of delamination on the sounds emanating from the panels and on the prevailing view driven by Kalzip, and the forceful Mr Carter, who formed and strongly held the view that the sounds he heard meant that inner skin delamination had occurred. I consider the expert evidence on these sounds at [196]–[204] below.

165 Mr Kolhatkar likewise sought to distance himself from his own assertions of delamination. He testified at trial that his earlier e-mails to Mr Carter (see [135], [140] and [147] above), which appeared to acknowledge that delamination was a problem, did not in fact represent BFG’s views. In his words, BFG was under “tremendous pressure” because Mr Carter “had a very aggressive personality”, and so had to attend to Kalzip’s complaints of delamination and formulate a remedial proposal while carrying out its own investigations to verify the reports of delamination. While BFG’s own investigations were underway in January and February 2010, Mr Kolhatkar did not express any doubt that delamination had occurred because his e-mails were “written in the spirit of a supplier/client relationship” with Kalzip. It was only around the start of March 2010, after BFG’s investigations were completed, that Mr Kolhatkar allegedly told Mr Carter that the only way to verify if delamination had occurred was to physically inspect the bottoms of the panels. ³⁶⁶ Mr Kolhatkar also referred to a meeting with Mr Flook, at which they agreed to assume that delamination had occurred so that BFG could work with Kalzip to resolve the problem. ³⁶⁷

166 Mr Kolhatkar’s account rings a little hollow for four reasons.

(a) First, if BFG was still unsure whether delamination had occurred in January and February 2010, it would have mentioned its doubts to Kalzip rather than accept that this was so. As Mr Kolhatkar himself said, “If the allegations were correct, there would have been serious commercial implications for BFG.” Moreover, he claimed that his communications to Kalzip on technical matters were “open, candid and truthful”. ³⁶⁸

(b) Secondly, Mr Kolhatkar himself agreed under cross-examination that this account was contradicted by the contents of his e-mail of 21 January 2010 to Mr Carter (at [135] above). He accepted that that e-mail was based on the assessment, judgment and report of an investigation team which he had despatched onsite, comprising persons who were in Mr Kolhatkar’s view amply qualified to investigate whether (and to what extent) delamination had occurred. ³⁶⁹ They included Mr Anand and Mr Rade, whom Mr Kolhatkar described as product experts. ³⁷⁰ He agreed that the reports of delamination from his team did not simply convey Kalzip’s allegations of delamination, but were reports of what the team assessed and judged for itself. ³⁷¹

(c) Thirdly, Mr Kolhatkar informed Dr Samer by way of an e-mail on 8 February 2010 that BFG’s site inspection and remedy trials discovered delamination on 60 GRP panels on the casino building in addition to the sound of crumbling aluminium honeycomb inside the GRP panels on the MICE building. ³⁷² Mr Kolhatkar had carefully distinguished between delamination and mere metallic noises in his e-mail to Dr Samer on 8 February 2010, which must mean that he recognised them as two legitimate and distinct concerns. This distinction also appears in Mr Kolhatkar’s previous e-mails on 29 and 30 January and 2 February 2010 (see [140], [142] and [147] above). Mr Kolhatkar testified that by 2 February 2010 he had concluded that “it was a mistake to equate these noises that were being heard on the panels [during the site surveys] with the panels having delaminated”. ³⁷³ Moreover, even if it were true that Mr Kolhatkar felt intimidated by Mr Carter, this could not explain why he felt the need to maintain the pretence that delamination had occurred to Dr Samer. Mr Kolhatkar agreed that his e-mails to Dr Samer would not have been subject to any such pressure. ³⁷⁴

(d) Fourthly, even after his alleged meeting with Mr Carter around the start of March 2010, Mr Kolhatkar sent further correspondence which appeared to accept that delamination had occurred. For example, on 3 March 2017, Mr Kolhatkar e-mailed Mr Carter regarding “the delamination problem noticed on the panels installed at CASINO and MICE sites”. ³⁷⁵ Similarly, on 7 March 2010, Mr Kolhatkar e-mailed Dr Samer and others from BFG. He wrote: ³⁷⁶

Mr Kolhatkar agreed that by his last sentence he was referring to the manufacturing process that took place in BFG Philippines. ³⁷⁷

167 It does not make sense for Mr Kolhatkar to have reported delamination to Dr Samer on the basis of his team’s report (see [166(c)] above), which he understood was based wholly on the noise heard from the panels, if he did not accept that this noise was indicative of delamination. Mr Kolhatkar ultimately conceded that, contrary to his initial position, “it [was] clear that BFG understood and accepted that there [were] delaminated panels on both the casino and the MICE buildings” based on “assessments and judgments reached by BFG’s site team”. ³⁷⁸

168 I therefore find that BFG did come to the view in around January and February 2010 that delamination had occurred in some of the panels on the casino and MICE buildings. This can be seen in the language used in BFG’s internal correspondence. However, this is subject to my comments on those e-mails which do express a residual doubt. Mr Attwood’s e-mail of 1 February 2010 (see [146] above) shows that he concluded that some casino panels had delaminated while the MICE panels had no delamination but were emitting noises when walked on. The members of BFG’s site team also inspected the site and arrived at the conclusion that delamination was a problem on the casino building and, to a lesser extent, the MICE building. This was reported to Mr Kolhatkar, who in turn reported to Dr Samer on 8 February that “[f]ew panels” on the MICE building showed signs of delamination while the casino building panels near the edge trim “show[ed] some delamination”, but which he attributed to the workers onsite jumping on the panels between bays (see [147] and [148] above). On the same day, Mr Rade reported to Mr Attwood that the MICE building suffered both from “[p]anels with patches of delamination” and “[p]anels where delamination is not evident but [there was] the metallic cracking sound” (see [150] above). This was a view that BFG arrived at based on its own site inspection. I therefore do not think that BFG was merely going along with Kalzip’s impression that delamination had occurred.

169 Notwithstanding the foregoing, I do find that manufacturing these panels with aluminium honeycomb, and in such large sizes, was something new to BFG. There were understandable doubts on BFG’s part and some lack of confidence in their product when vigorously attacked by Kalzip; this gave rise to internal finger-pointing within BFG. As I have pointed out above at [122]–[162], these e-mails, read fairly, also show that BFG was not completely certain that delamination due to defective manufacturing had occurred. I have noted above that no panel emitting crunching or crinkling noises was taken off its fixings for inspection to confirm that delamination had occurred. Even Mr Attwood can be seen to be changing his views of the cause of delamination. They swung from mishandling by Kalzip to crumbling or failure of the aluminium honeycomb, a hypothesis which no one pursued at trial. I also note that these e-mails covered only a short span of time, a time when matters suddenly boiled over and came to a head in January to early March 2010.

170 Even accepting that BFG’s own personnel accepted that delamination had occurred, the question in this suit is whether they were correct to do so. For the same reason, the fact that BFG submitted a remedial proposal to Kalzip can only take Kalzip so far. I also conclude that the correspondence is not determinative of Kalzip’s case for the following reasons:

(a) First, the significance of the sounds emanating from the panels when walked upon is an important issue. It was these sounds which led Mr Carter, Mr Attwood and Mr Mackay to form the view that the panels had delaminated, thus leading to much of the correspondence described above (see [126], [138], [144], [145], [156]–[158] above and [180] below). Mr Kolhatkar likewise received reports of delamination from his team which he understood to be based in turn on the noise that was reported to come from the panels onsite. ³⁷⁹ However, he maintained at trial that “the noise observed in the aluminium honeycomb while walking on the panels is due to the Metal FRP Interface and does not represent any panel failure”. ³⁸⁰ This requires a closer consideration of the sounds allegedly made by the GRP panels, which I return to at [177] below.

(b) Secondly, Kalzip claims that the delamination was “extensive” based on the four site surveys described above. However, these appear to have been recorded on the premise that the sounds emitted by the panels were evidence of delamination.

(c) Thirdly, BFG lacked experience manufacturing panels of this type of such a large size (see [362]–[364] below), and may therefore have been mistaken in concluding that delamination had occurred. I have already made this point at [122] above.

(d) Fourthly, even if BFG accepted that some panels had delaminated, that would only constitute a breach of contract on BFG’s part if the delamination occurred because the panels were defective in the first place. As will be seen, BFG alleges that any delamination which occurred is attributable to the panels having been misused onsite.

171 Kalzip makes much of the fact that the surveys were conducted jointly in the presence of representatives from both MBS and BFG, none of whom raised issues with the methodology adopted or challenged the allegation of delamination. ³⁸¹ However, I do not accept the site surveys themselves as evidence of delamination, for the following reasons.

172 First, it is not totally clear whether these surveys recorded areas which emitted a particular sound (as Mr Kolhatkar ³⁸² and Mr Flook ³⁸³ claimed), or which both “exhibited signs of sagging and emitted cracking sounds when walked upon” (as Mr Mackay claimed). The surveys themselves do not contain any legend stating the significance of the yellow annotations. Mr Mackay agreed that it was impossible to tell from the surveys which panels may have exhibited signs of sagging. ³⁸⁴ Insofar as the surveys were based on crinkling or crunching sounds, I accept Mr Wymond’s and Mr Maurieschat’s evidence that the crinkling sounds alone were not evidence of delamination (see [205] below).

173 Secondly, there is much that is not clear about the surveys. For one, it is not clear who attended which surveys. According to Kalzip’s Further and Better Particulars in the arbitration, the attendees were as follows: ³⁸⁵

(a) 6 and 25 February 2010: Mr Carter (Kalzip), Mr Leong (Kalzip), Mr Peter Morgan (Aedas), Mr Jan Oebeles (BFG) and Mr Peter Dooley (BFG)

(b) 2 and 8 March 2010: Mr Lenny Hill (Kalzip), Mr Leong (Kalzip), Mr Ted Mahoney (BFG), Mr Peter Morgan (Aedas)

174 None of these persons were called to testify in the present suit. Instead, Kalzip’s witnesses in the present suit claimed to have attended the site surveys (though, significantly, none of them claimed to be responsible for actually annotating the surveys). For example, Mr Attwood said that he participated in “some” of the surveys but could not recall if he was present at the surveys on 2 and 8 March 2010. ³⁸⁶ Mr Mackay recalled attending “at least one or two surveys” but could not remember the actual dates and said that Mr Leong was “more in charge of doing the surveys itself”. He was willing to accept that he “may not have been on [the 6 February 2010] survey”. ³⁸⁷ BFG submits that “there is no evidence at all” to show that Mr Mackay attended any of the four site surveys and the court should therefore give little weight to his evidence about the surveys. ³⁸⁸

175  Thirdly, it is not true that BFG raised no objections to Kalzip’s methodology of assessing delamination. As I have noted, Mr Kolhatkar sent an e-mail on 2 February 2010 to Mr Carter explaining that the metallic noises emanating from the panels on the MICE building roof were a “normal phenomenon” and that the panels themselves did not show signs of delamination (see [147] above). This explanation was included in the report jointly compiled by Mr Attwood, Mr Anand and Mr Rade ³⁸⁹ (see [148] above). Besides this written evidence, Mr Rade testified that he had raised an objection to Mr Carter about jumping on the panels to test for delamination (see [145] above).

176 More importantly, as Kalzip itself says, BFG’s internal communications, the four site surveys and the evidence given by its key witnesses at trial at best establish that “BFG accepted that the GRP panels produced for the Project had delaminated” [emphasis added]. ³⁹⁰ While BFG did occasionally raise concerns about the methodology used to identify delamination, the correspondence between the parties and within BFG internally establish that BFG accepted that delamination had occurred. However, whether the panels in fact delaminated is a different issue. Mr Carter, who related the sounds of “crunching” to the phenomenon of delamination, was described by Kalzip as “lack[ing] the necessary expertise in GRP, a highly specialized composite material”. ³⁹¹ I therefore turn to the sounds which were described.

177 The noises made by the panels when walked or stepped on were variously described as “cracking”, “crackling”, “crunching” and “crinkling” by different persons. They are described in much of the correspondence as “metallic” sounds. The variety and subjectivity of these descriptions make it difficult to identify exactly what sounds were heard, and what they could have been caused by. Mr Mackay’s evidence exemplifies these difficulties. He used the first three terms in the following ways:

(a) Mr Mackay allegedly heard “cracking” sounds when walking on the panels in January 2010, as well as during site inspections on 26 February 2010 and 2 March 2010 (see [126] and [157] above). Mr Mackay seemed to equivocate this to deep “crunching” sounds, and associated this sound with sponginess of the panel (see [126] above).

(b) Three of the four site survey diagrams, which were shaded to show delamination, allegedly captured panel sagging and “crackling” sounds (see [149], [154] and [157] above). In his AEIC, however, Mr Mackay stated that a “crackling” sound was indicative of crushed honeycomb or resin-coated honeycomb and could be contrasted with “crunching” sounds (see [220] below). The fourth site survey, on 8 March 2010, is described in terms of “cracking” sounds (see [158] above) but Mr Mackay stated during cross-examination that this was probably a typographical error and was meant to be “crackling”. ³⁹²

178 During cross-examination, Mr Mackay distinguished these sounds as follows: ³⁹³

179 Mr Mackay therefore agreed that the “crackling sounds” allegedly recorded in the four site surveys could not be relied upon to suggest delamination. However, he then said that there were also deeper crunching sounds, but he could not remember at which (if any) of the four site surveys he had attended that he heard these crunching sounds, or the ratio of crackling to crunching sounds heard. ³⁹⁴

180 I place no weight on Mr Mackay’s evidence on the significance of the various sounds. He was a factual witness, not an expert witness, and was prepared on that basis to withdraw his opinion that crunching sounds indicated structural failure. ³⁹⁵ Moreover, his view that the sounds emitted by the panels were indicative of delamination appears to have been based on Mr Carter’s assertions. According to Mr Mackay, Mr Carter told him that the noise emitted was the same as sounds which he had heard during factory inspections in 2008 and 2009, when they were indicative of inner skin delamination. ³⁹⁶ But Mr Mackay was not present at those inspections and could not vouch for the accuracy or veracity of Mr Carter’s view: ³⁹⁷

181 Mr Carter himself was not a witness in the Suit. His conclusion that noise was indicative of delamination was wrong, because the samples which delaminated during the two factory visits were not representative of the actual GRP panels. They differed in one or more of the following ways: (a) they were smaller than an actual GRP panel, were not edge-sealed and may not have had Z-strips; (b) they had not been made using the intended reinforcements and resin; and (c) they had not undergone vacuum-bagging. I have explained in detail at [110]–[121] above why the factory inspections of 3 September 2008 and 23 April 2009 did not in fact show evidence of delamination. Mr Mackay also conceded that it was “pure conjecture or speculation” to conclude that the lower face of a panel which produced those sounds had delaminated, because it was impossible to actually see the inner skin while walking on the panels. ³⁹⁸ Mr Mackay’s evidence suggests at best that he did in fact hear the sounds which he described. I should add that, unlike Mr Mackay, Mr Attwood and Mr Rade did not distinguish between two types of sounds; they described what they heard (and what was heard on the panels during the site surveys) only in terms of “crunching” sounds.

182 I now turn to the expert evidence on the significance of these sounds. The experts relied heavily on the 2015 Tests in forming their conclusions about the significance of the sounds. I first describe these tests and their results before turning to the experts’ opinions.

183 As none of the original GRP panels which were actually installed in the Project were preserved, Mr Wymond commissioned BFG to manufacture and test additional panels for the purpose of the 2015 Tests. A series of sample panels was made, supposedly in the same way that the GRP panels had been manufactured. Each sample panel measured approximately 6m long and 3m wide with inserts and clips at 800mm spacing on each side and staggered at 400mm centres along the centre of the panel. ³⁹⁹ Nine panels were tested: seven that were standard, and two that were manufactured so as to have “floating” inner skins – ie, inner skins that were totally delaminated. The seven standard panels were tested in the following way, and with the following results: ⁴⁰⁰

(a) First, a point load test was carried out by imposing a statically-applied load of 1.1 kN on the panels. No local damage was caused to the panels. A tap test was carried out on the underside of the panel after the test and no delamination was recorded.

(b) Secondly, a positive pressure test was carried out by first pre-loading the panel and then loading it to 0.75 kPa. The deflection readings were consistent with the calculations. A tap test was carried out on the underside of the panel after the test and no delamination was recorded.

(c) Thirdly, a negative pressure test was carried out by first pre-loading the panel and then loading it to -2.0 kPa. The deflection readings were consistent with the calculations. A tap test was carried out on the underside of the panel after the test and no delamination was recorded.

(d) Fourthly, a cyclic maintenance loading test was carried out. This involved five men (weighing between 69kg and 110kg) taking turns to walk across one half of a 6m by 3m panel in a zigzag pattern, each man walking 20 cycles, making a total of 100 cycles. ⁴⁰¹ According to the test report, the noise of aluminium honeycomb crinkling was present and consistent throughout and there was no difference in noise from variations in a person’s weight or with the number of cycles. ⁴⁰² A tap test was carried out on the underside of the panel after the test and no delamination was recorded.

(e) The panels were then subjected to a repeat positive pressure test and repeat negative pressure test as at (b) and (c) above. The panels did not deflect much more than they had prior to undergoing the cyclic maintenance loading test. The two halves of the panel (only one of which was walked on during the cyclic maintenance loading test) had approximately equal deflections.

184 The two panels with “floating” inner skins were subjected first to a positive pressure test (0.75 kPa), then to a negative pressure test (-2.0 kPa), then to walking. The deflection readings were consistent with calculations (ie, not excessive).

185 Following these tests at Kaskal on 17 and 18 August 2015, smaller segments were cut from both the standard and delaminated panels which had been tested and sent to Fraunhofer IFAM for further tests. ⁴⁰³ Mr Maurieschat also obtained cut samples from some panels which had originally been produced for installation in the Project, but which were never installed because they exhibited defects, for example scratches in the gel coat. ⁴⁰⁴ These panels had therefore been left in the Philippines. BFG personnel selected some of these for testing ⁴⁰⁵ , cut 11 samples from three panels selected at random ⁴⁰⁶ , and sent the cut samples to Mr Maurieschat. The only evidence that these cut samples had come from the panels manufactured for the Project was that each was labelled with a code from “OL-1” to “OL-11”. ⁴⁰⁷ The following tests were then conducted at Fraunhofer IFAM on 14 September 2015:

(a) Noise tests: specimens which had not been charged with any load before were mounted in a sample and subjected to a compression load exerted through a dolly. The compression load was gradually increased until the first crinkling sound was heard, at which point the load was recorded. These tests showed that the panels manufactured exactly as per the documented materials and manufacturing processes began producing crinkling sounds at about 20–40kg of force. The test panels did not exhibit any delamination and were then subjected to direct pull-out tests (also referred to as tensile tests) to test their structural adequacy. ⁴⁰⁸

(b) Direct pull-out tests, also referred to as tensile tests: 20cm-by-20cm samples were cut out of each panel sample and cored with a diameter of 117mm. Only the inner skin of the sample was cored; the aluminium honeycomb was not torn or subjected to significant pressure. ⁴⁰⁹ The inner layers of the test samples were bonded with a dolly and then subjected to a pull-out test by a testing machine with a 20 kN load cell. The results showed that there was sufficient adhesion between the aluminium honeycomb and the inner skin even though the specimens had begun making crinkling noises. ⁴¹⁰

186 Kalzip and its experts raise various arguments to cast doubt on the reliability and persuasiveness of the 2015 Tests. I examine these in turn and explain why I am not persuaded by them.

187 First, Kalzip attempts to discredit the 2015 Tests by casting doubt on the provenance and suitability of the samples allegedly derived from panels produced in 2010. ⁴¹¹ Mr Wymond did not personally investigate the provenance of these panels and appears to have simply accepted on the faith of photographs showing the tag markings of the panels set into the panels by resin that they were indeed panels from the original production run. ⁴¹² BFG witnesses did not mention any of these original panel samples. Mr Wymond could not comment on the suitability of the panels for testing from a material perspective, and agreed that there “may have been an issue” if, for example, the panels had been “stored in a way that had caused corrosion or some sort of deterioration” or if the panels were “subject to a cyclone in the Philippines”. ⁴¹³

188 I am not persuaded by Kalzip’s submission. Mr Maurieschat, who received the samples from BFG, confirmed that he had visited BFG’s Philippines facility before the preparation of the samples and personally saw those panels onsite labelled with their production dates. He also received a report from Mr Rade as proof that the samples which were sent to him were extracted from the original panels for the Project. ⁴¹⁴ As for the suitability of the panels, Mr Wymond’s concern was that the original panels may have deteriorated with time depending on the conditions of their storage. There would be no reason to expect them to have performed better in the 2015 Tests than they would have in 2010.

189 Mr Green and Mr Wymond agreed that if the GRP panels supplied to the Project were identical to the test panels used in 2015, they would have met the Sub-Contract requirements. Prof Nonhoff likewise accepted that Mr Maurieschat’s pull-out test ⁴¹⁵ , assuming the results were accurate, showed that the samples achieved a good bond between the aluminium honeycomb and the inner skin, and that if the GRP panels had shared these characteristics, they would not have delaminated. ⁴¹⁶ However, whereas Mr Wymond took the view that the panels were made to the same specification and had the same composition, ⁴¹⁷ Mr Green thought that the panels tested in the 2015 Tests were not representative of the panels supplied to the Project. ⁴¹⁸

190 Mr Maurieschat and Mr Premamoorthy gave evidence that the same quality control and manufacturing documents were used in 2009–2010 and in 2015 ⁴¹⁹ , and that the 2015 Test panels had been through an identical manufacturing process as that used in 2009–2010 (described in detail at [316] below) ⁴²⁰ , save for minor deviations which were unlikely to have any impact on the performance of the panels to the specifications. ⁴²¹ At trial, however, Mr Maurieschat and Mr Premamoorthy agreed that there were three differences between the manufacturing process in 2009–2010 and that used in 2015, in relation to how the inner skin was manufactured after the aluminium honeycomb and upper skin were subjected to vacuum-bagging:

(a) In 2009–2010, after the vacuum-bagging process, the three layers of matter which would comprise the inner skin of the GRP panel were introduced to the mould one at a time. In 2015, however, the three layers were introduced to the mould together. ⁴²²

(b) In 2009–2010, resin was applied to the first layer of chopped strand mat (“CSM”) 225 (a process known as “pre-wetting”) before it was introduced to the mould. In 2015, the three layers were dry when they were introduced to the mould. ⁴²³

(c) In 2009–2010, the layers were laid flat on the aluminium honeycomb in the mould. In 2015, the layers were folded. ⁴²⁴ I note there was some disagreement over how exactly they were folded. According to Mr Maurieschat, the three layers were folded down the middle and resin applied to them as folded; they were then unfolded and more resin applied; they were then folded again in the other direction and resin applied; and finally they were unfolded and resin applied again. According to Mr Premamoorthy, resin was applied as each of the three layers were folded one at a time. ⁴²⁵ Regardless of this difference, the fact remains that they were folded, whereas the layers in 2009 were not. (I note that Mr Premamoorthy subsequently said that there was folding in 2009 ⁴²⁶ , but this was not described in his AEIC and appears to have been an afterthought.)

191 Mr Maurieschat considered that these differences were not important or material; they were simply alternative ways of introducing the CSM to the mould. ⁴²⁷ Nor did the other experts testify that these differences would have led to differences in performance between the GRP panels produced in 2009–2010 and the test panels produced in 2015. I therefore do not find that these differences in manufacturing process invalidate the conclusions of the 2015 Tests.

192 Kalzip seeks to discredit Mr Maurieschat’s view that the differences between the two manufacturing processes were unimportant and immaterial, on the basis that his knowledge of the 2009–2010 manufacturing process was limited. In particular, Mr Maurieschat only conducted a desktop review of the 2009–2010 manufacturing process and only saw one process control sheet (“PCS”) – a document recording critical parts of the manufacturing process for the panel – from the 2009–2010 production run even though there ought to have been one PCS per panel for 3,421 panels. ⁴²⁸ The one PCS which Mr Maurieschat obtained was for panel 16 of bay 7 of the MICE building roof, which was indicated on the site survey dated 8 March 2010 as non-delaminated. ⁴²⁹ Indeed, Mr Maurieschat conceded that he ought to have asked for more PCS. ⁴³⁰ However, I do not agree that this invalidates Mr Maurieschat’s opinion. Mr Maurieschat personally audited the 2015 manufacturing process, and Mr Premamoorthy helped to develop the 2009–2010 manufacturing process. ⁴³¹ Together they were able to provide a reliable comparison of the two processes. Absent any positive evidence that the manufacturing processes as described by Mr Premamoorthy and Mr Maurieschat were inaccurate or not adhered to, I see no reason to doubt their descriptions thereof. There is nothing to contradict Mr Maurieschat’s opinion that the differences would not have been material to performance.

193 I therefore do not think that the 2015 Tests are unreliable simply because of differences in the manufacturing process between 2009–2010 and 2015. Even if this criticism were valid, it would not apply to the tensile tests conducted by Fraunhofer IFAM on panels which had been manufactured in 2010. Moreover, a shear test conducted by Fraunhofer IFAM showed that the minimum strength of the 2010 panels was greater than that of the new panels, thus suggesting that the 2015 test panels were not deliberately made stronger for the purpose of testing. ⁴³²

194 When asked about the 2015 Tests performed by Mr Maurieschat, Prof Nonhoff said he thought that most of these were done “properly and right”, but that the “boundary conditions” for some tests were “not right”. ⁴³³ The noise test specimens differed from the GRP panels in a few ways:

(a) In the noise test, the force from the dolly was applied to a sample measuring 200cm by 200cm, which was much smaller than an actual panel.

(b) The noise test sample lay on a square frame, whereas the GRP panels would have lain on three rails, and stepping in between two rails could have produced a different effect from stepping on a part of the panel lying directly over a rail. ⁴³⁴

(c) The noise test samples had exposed edges, unlike the GRP panels. ⁴³⁵ In Prof Nonhoff’s view, the samples “exhibited crinkling noises because the edges of the panel were free”. ⁴³⁶

195 Mr Maurieschat’s response to these points was that it did not actually matter whether the GRP panels would also have emitted sounds under these conditions; the noise test was undertaken purely for the purpose of verifying whether the emission of such noises was necessarily proof of delamination. ⁴³⁷ I accept his explanation. There is no apparent reason, and Prof Nonhoff did not offer any, why the difference in boundary conditions should disturb Mr Maurieschat’s conclusions about the correlation between the noises emitted and the presence of delamination.

196 Mr Wymond’s expert view was that the sounds could not necessarily be correlated with deformation of the honeycomb. The 2015 Tests showed that crinkling did not necessarily show any structural inadequacy:

(a) The cyclic maintenance loading test during the 2015 Tests showed that the crinkling or crunching sound did not indicate delamination or structural inadequacy. Even though a crinkling sound was present over many cycles of walking, the panels which produced these sounds were not delaminated at the end of the test. ⁴³⁸

(b) The tests conducted at Fraunhofer IFAM showed that noise occurred as a result of applying pressure directly to the GRP panels, but no delamination occurred and there was no change to the structural performance of the test specimens. ⁴³⁹ Indeed, during the noise test, samples which emitted crinkling sounds in the range of 475N to 647N were nevertheless able to carry loads of between 1100N and 2078N. ⁴⁴⁰

197 Mr Maurieschat also relied on the 2015 Tests for his conclusion that there was no evidence of delamination in the panels which Prof Nonhoff claimed to have observed. ⁴⁴¹ These tests showed that the panels began producing crinkling sounds at about 20–40kg of force, leading Mr Maurieschat to conclude that someone walking on the panels would be enough to cause them to generate crinkling noises. ⁴⁴² However, these same panels were not delaminated and the direct pull-out tensile tests showed that they were able to withstand specified loads even though they had produced crinkling noises. ⁴⁴³

198 If that is the case, what caused the GRP panels to make the sounds which were heard? I reiterate that at least two different sounds were heard by Mr Mackay: a lighter crinkling sound and what Mr Mackay described as a “deep crunching sound”. Mr Maurieschat opined that the noises were simply a characteristic of the panels – specifically, a result of extra resin pooling at the junctions of the upper skin (ie, the lower layer of fibreglass in the mould) and the aluminium honeycomb. When forces were applied to the panel (for example, people walking on it), the resin would start chipping off with a cracking noise and there would also be a crinkling noise as a result of the basic aluminium honeycomb foil spring action. The two of these noises together might be described as cracking and/or crinkling noises. The noise of the resin chipping off would stop after the panels had been walked on several times, whereas the crinkling noise of the deformation of the aluminium honeycomb foils would continue. This suggested that the crinkling noises heard during the 2015 Tests were not due to delamination, since they would have stopped after the panels delaminated if that were the case. ⁴⁴⁴

199 Mr Wymond took the same view. He observed that, during the walking test, the panels did not initially produce a crunching sound but began producing a consistent crunching sound after a few cycles of walking. This was “consistent with the upper skin initially providing a load spreading platform through excess resin in the honeycomb, but once the excess resin was cracked the panels made a regular and consistent crinkling sound with each step”. This sound was not an indicator of delamination but was due to deformation of the honeycomb. ⁴⁴⁵ At trial Mr Wymond stated (and Mr Maurieschat agreed): ⁴⁴⁶

200 Kalzip relies on this statement in support of the proposition that “a delaminated panel would produce a ‘crunching’ sound if one was to walk on it”. ⁴⁴⁷ But that is not how I understand Mr Wymond’s evidence. The phenomenon that he and Mr Maurieschat were referring to was when excess resin that had flowed over the honeycomb cracked. ⁴⁴⁸ Mr Maurieschat explained this in the following terms: ⁴⁴⁹

201 BFG’s experts therefore took the position that the sounds emitted by the panels were not indicative of delamination. I pause here to note that though BFG’s experts attributed the sounds to deformation of the honeycomb, Kalzip has not alleged any contractual breach on BFG’s part in relation to such deformation.

202 Prof Nonhoff thought that the crunching noises that he had heard were “symptomatic of structural failure” and “indicative of” delamination. ⁴⁵⁰ He disagreed that crinkling or crunching noises were characteristic of GRP panels. Prof Nonhoff attested to having walked across a lot of panels with a honeycomb construction in his career, and never having heard any crinkling sounds, ⁴⁵¹ though he thought it “perfectly normal” to hear a light crinkling sound when stepping around the edges of a cored hole. ⁴⁵² By contrast, an intact panel would only produce crunching noises “if one of the face layers is delaminated or the honeycomb is crushed locally”. ⁴⁵³ In his view, “[i]f a panel with a sandwich construction is properly manufactured then practically no sound should be audible”. ⁴⁵⁴ He stated: ⁴⁵⁵

203 Prof Nonhoff disagreed that the crunching or crinkling sounds arose from excess resin at the junction of the upper skin and the aluminium honeycomb, because he had not observed any such excess resin in the panels he inspected in 2010. The noises arose only because of delamination. ⁴⁵⁶ Against this, however, I note that Mr Maurieschat’s expert report contained close-up photographs of the upper skin, which he had annotated with the following comments: “Dropped down resin onto the backside of the outer skin” and “Cracks in the surface of the dropped down resin”. ⁴⁵⁷ Although Mr Maurieschat made this point at trial with reference to these very photographs, Prof Nonhoff did not contradict Mr Maurieschat or express any disagreement. ⁴⁵⁸

204 Mr Green stated that he knew “for a fact” that mere noise of the core was not a normal phenomenon observed in aluminium-cored composite cladding panels, because he had dealt with such panels and had walked on them without hearing any noise. ⁴⁵⁹ However, Mr Green’s assertion lost much of its force when he conceded that he had never walked on a fibreglass panel with an aluminium honeycomb core, as he had not encountered one prior to this case. He had only had experience with an aluminium-faced honeycomb panel. ⁴⁶⁰ Mr Green stated that he did not profess to be an expert on any aspect of fibreglass skinned aluminium honeycomb panels, as that was Prof Nonhoff’s realm. ⁴⁶¹ He had also never worked with a product that combined aluminium with fibreglass reinforced plastic. ⁴⁶²

205 Having considered the expert evidence, I have formed the view that the sounds heard from the panels (and which formed the basis for the four site surveys), whether described as crunching, crinkling or cracking noises, were not indicative of delamination. The idea that the crunching noises were indicative of delamination appears to have lodged itself firmly in the mind of Mr Carter at the time of the factory inspections on 3 September 2008 and 23 April 2009. Mr Carter was a forceful figure and was adamant that the noises emitted by the GRP panels were proof of delamination. ⁴⁶³ This is borne out by his e-mail to Mr Kolhatkar in early March 2010, in which he referred to a video that Mr Kolhatkar had sent; Mr Carter considered that “the existing delamination is clearly evident from the audio in this video” [emphasis added]. ⁴⁶⁴ He then propagated this idea to Mr Mackay (see [180] above) and used it to test for the presence of delamination onsite. ⁴⁶⁵ But surprisingly, none of the panels which produced sounds were taken off their fixings to confirm that they had in fact delaminated. This was the case even after MBS made the decision to engage another contractor to replace all the GRP panels with aluminium panels. Mr Mackay, as noted at [181] above, conceded as much in cross-examination and agreed that it was “conjecture or speculation” to say that the inner skin had delaminated based on the sounds heard when walking on the panels “because it was impossible to view the lower face or bottom skin”. ⁴⁶⁶ The experts could not agree whether the sounds were evidence of delamination. I find that the 2015 Tests constitute objective and convincing evidence that the presence of such sounds does not indicate delamination. This is corroborated by Kalzip’s core sampling video from 2 March 2010, which showed that crinkling sounds were made by cored panels even if the core samples were not delaminated. Insofar as the BFG correspondence was based on those sounds, I do not find them to be proof of delamination.

206 The earlier correspondence from BFG appears to have proceeded on the assumption that the sounds were evidence of delamination. Mr Attwood’s e-mail on 7 December 2009 was based on Kalzip’s report of delamination, probably based in turn on the sounds that had been heard, and his e-mails on 11, 18 and 27 January 2010 were likewise based on those sounds. Importantly, however, there were various internal e-mails from end January to February 2010 which distinguished between the problem of delamination and the mere emission of metallic or “ALHC” (aluminium honeycomb) sounds (see [140], [146], [147], [148], [150], [152] and [166(c)] above). Indeed, Mr Kolhatkar testified that by 2 February 2010 he had concluded that “it was a mistake to equate these noises that were being heard on the panels [during the site surveys] with the panels having delaminated”. ⁴⁶⁷ Unfortunately those e-mails do not say what other signs (besides the noises, which were a different problem) led the team to deduce delamination, or how widespread these were. Mr Kolhatkar was unable to explain why he had reported delamination if he did not think that the noises were proof of this, though he also mentioned that “there are six panels on which they had done the local drilling”. ⁴⁶⁸ Mr Attwood’s e-mail at [146] mentions “drilling into panel front [face] and examining the aluminium honeycomb”. What sort of drilling this was and what the examination of the aluminium honeycomb showed were not explored at trial with either Mr Attwood or Mr Kolhatkar. Indeed, Kalzip did not give much attention to these e-mails, preferring to focus on the noises as evidence of delamination. However, as I explain below, there were other phenomena besides the noises – for example the fact that some panels deflected underfoot – that appear to have led BFG to conclude that delamination had occurred (see [225]–[226] below).

207 That concludes, for the present, my analysis of the correspondence from BFG and the four site surveys. I now move on to other evidence of delamination.

208 Around 20–21 June 2010 ⁴⁶⁹ , Prof Nonhoff visited the Project and inspected both the MICE and casino building roofs. He walked the length of the MICE building roof and inspected “a large number of panels”, and conducted a more limited inspection on the casino building roof. ⁴⁷⁰ On both roofs, Prof Nonhoff noticed that a lot of the panels made loud crunching noises; he states that his investigation established that these sounds were a result of delamination: ⁴⁷¹

(a) Prof Nonhoff knelt on the panels to identify the cause of the noise, and it was clear to him that the noises were coming from the panels themselves and not from the connections to the Kalzip roof.

(b) At two different positions where he heard loud noises and observed deformation, the inspection team cored circular samples from the panels. ⁴⁷² These panels showed complete delamination of the inner skin and delamination around the perimeter of the core hole, thus establishing that the crunching noises were indicative of delamination. ⁴⁷³ A photograph of a cored sample shows that the inner GRP face of the cored sample had delaminated from the aluminium honeycomb core. ⁴⁷⁴ Another photograph of the perimeter of the cored hole in a panel in situ shows that the inner face had delaminated sufficiently from the honeycomb core for a €1 coin (approximately 2mm thick) to be wedged between them. ⁴⁷⁵

209 Prof Nonhoff also “saw deformations of large areas when [he] and the other people stepped on the panels”. ⁴⁷⁶ It was clear to him that the weight of the individuals walking on the panels was causing “significant deformation”. In his view, this was only possible because the panels were not made correctly; if the panels had been made correctly, they could be walked on without any problem. ⁴⁷⁷

210 I note that Prof Nonhoff has an advantage over the other experts in that he managed to visit the panels onsite in 2010. However, his evidence does not satisfy me that widespread delamination occurred on a balance of probabilities, for the following reasons:

(a) Prof Nonhoff thought that the four site surveys were “consistent” with the delamination he had observed. ⁴⁷⁸ In his view, the “load-bearing ability of the GRP panels was clearly impaired by the delamination of the inner face”. ⁴⁷⁹ However, Prof Nonhoff accepted at trial that he was not present onsite in February and March 2010, and could not correlate whatever sounds Kalzip personnel had heard in those months to the sounds that he personally heard in June 2010. While the noises heard by the Kalzip personnel had been described to him, and he had formed “an idea” of what they were, he admitted that noises could be interpreted differently by different people. ⁴⁸⁰

(b) There is no documentation of Prof Nonhoff’s inspection; he agreed during cross-examination that his inspections in 2010 were so poorly documented that it was impossible to know what he had actually seen or heard. ⁴⁸¹ I do not expect this of an expert giving expert evidence before me. As an illustration, Aedas’ report of 22 January 2010 (see [227] below) carefully documented the problems reported onsite, with photographic evidence and comments, as well as identified the panels and components in question. In contrast to Prof Nonhoff’s assertions that panels which produced crunching sounds had delaminated, the 2015 Tests provide objective evidence that such sounds do not show delamination.

(c) The only evidence from Prof Nonhoff’s inspection is the two photographs he adduced of the cored samples. However, there is no video of the coring, so it is impossible to tell if the coring was performed properly or not. ⁴⁸² BFG submits that the coring process would have exerted vibration forces causing the delamination. ⁴⁸³ While Prof Nonhoff stated that he was present during core sampling and observed that the circular samples were cored carefully with reduced cutting speed, ⁴⁸⁴ Mr Wymond considered that delamination could occur as a result of other variables in the coring process even if the coring was done properly. ⁴⁸⁵ Moreover, the coring was only carried out at two areas, ⁴⁸⁶ whereas Kalzip alleges that widespread delamination occurred across the hundreds of panels installed.

(d) Prof Nonhoff acknowledged that in June 2010 and while preparing his first expert report, he had assumed that there was delamination of the inner skin (as opposed to concluding that this was the case from his own survey of the evidence). It was only in his rebuttal report that he referred to evidence of delamination. ⁴⁸⁷ He also agreed that he had “not discharged [his] expert obligations to properly analyse the nature and extent of the alleged delamination”, ⁴⁸⁸ and that delamination occurred only in very localised and limited areas of the Project roofs. ⁴⁸⁹

(e) Prof Nonhoff’s view that the GRP panels “clearly did not meet the requirements of Specification Revision C” was based on the structural tests which I have discussed above and Mr Green’s analysis of those tests. ⁴⁹⁰ For the reasons I have stated, these tests were not reliable evidence of delamination, because they appear to have failed for other reasons (see [75]–[97] above). ⁴⁹¹

211 Besides the noises emitted by the panels, another phenomenon observed by Mr Mackay and Prof Nonhoff was that there were areas of the panels which felt “spongy” underfoot and/or deformed when walked upon (see [126] and [208] above). Mr Mackay correlated this to the crunching sounds: ⁴⁹²

212 While Mr Rade denied that the panels would become “spongy” when delaminated, he did say that delaminated panels would “deform more” when walked upon ⁴⁹³ and that your feet would “sink in more”. ⁴⁹⁴ However, he did not observe any such deformation during the site inspection on 1 February 2010 ⁴⁹⁵ , nor did Mr Premamoorthy when he walked on the panels in January 2010. ⁴⁹⁶

213 BFG submits that what Mr Mackay described as “sponginess” when walking on the panels was simply the natural bounciness they possessed given the deflection limits to which they had been designed. ⁴⁹⁷ I do not agree as that was not what Mr Mackay meant. Mr Mackay was clear that when he was walking across the roof, he would come to “a spot where it would be a deep crunch and very spongy” [emphasis added] and that it “wasn’t like on the rest of the panels, where it was fairly solid” (see [126] above).

214 Mr Green was unable to comment on whether “spongy” was an appropriate term in this case, having never seen the GRP panels, walked on them or performed tests on them. ⁴⁹⁸ Mr Wymond said that “sponginess” was not an engineering term that he would normally ascribe to the performance of a material; it was more appropriate to talk about how much a panel was deflecting underfoot. ⁴⁹⁹ The experts agreed that a panel designed to experience greater deflections would naturally feel less firm to someone walking on it; but the rate at which it recovered from that downwards deflection would be a function of elasticity and other characteristics of the panel. ⁵⁰⁰ As Mr Kolhatkar said, it was part of the “natural characteristics” of a panel for it to deflect and return to its original shape when walked on, ⁵⁰¹ within the deflection limits to which it was designed.

215 Kalzip’s position was that a properly manufactured panel should be firm and should not deflect when walked upon. ⁵⁰² The experts appeared to be in agreement that deflection underfoot was abnormal:

(a) Mr Green said that if a panel deflected underfoot, resulting in a depression, that would suggest that there was something wrong with it, though he could not say whether it would be due to crushing of the honeycomb or delamination. He would not expect a panel to behave like that ordinarily. ⁵⁰³

(b) Prof Nonhoff agreed that deflection underfoot was abnormal. A panel whose lower layer had delaminated from the honeycomb would be “softer” and deform more underfoot because the shear forces could not be transferred. If the foot was lifted from the panel, it would come back to its original position but not as quickly as an intact panel. ⁵⁰⁴ However, he did not think this would occur as a result of the honeycomb giving way. In that situation, one would not feel any deformation because the upper skin would be hard and thick enough to support one’s weight. ⁵⁰⁵

(c) Mr Wymond agreed with Prof Nonhoff because the 2015 Tests showed that a delaminated panel deflected more than a non-delaminated panel when stepped on. ⁵⁰⁶

(d) Mr Rade – who, though strictly speaking a factual witness, was a structural design engineer and had been working with composite designs and technology for many years ⁵⁰⁷ – also said that if one stood over a delaminated area of a GRP panel, one would expect to see the panel sag or deform. Apart from sagging, it would not be possible to visually observe delamination from the top of the panels and Mr Rade saw none. ⁵⁰⁸

216 I note that Mr Maurieschat said that he would expect “some spongy feeling beneath your feet” while walking on a GRP panel which had nothing to do with delamination of the bottom layer or deformation of the honeycombs. BFG relies on this to say that the phenomenon of deflection underfoot does not indicate delamination. ⁵⁰⁹ However, I do not think that is what Mr Maurieschat meant. He said: ⁵¹⁰

217 As I understood him, Mr Maurieschat meant to say that a GRP panel would ordinarily feel less firm than a concrete roof. However, he was quite clear that he had not personally experienced one GRP panel sinking or deflecting underfoot in a particularly pronounced way. This corroborated the other experts’ views that a panel which did so would be abnormal.

218 However, the evidence of panels deflecting underfoot does not persuade me that widespread delamination occurred. First, only Mr Mackay and Prof Nonhoff positively attested to having experienced such deflection underfoot. Mr Rade and Mr Premamoorthy denied having experienced this. Moreover, Mr Mackay’s description of the deflections appears to have been exaggerated. His descriptions of a foot “sag[ging] into the panel itself” and “[giving] into the panel” and of panels being “very spongy” at a particular “spot” gave the impression of a foot, importantly not both feet, suddenly sinking deeply into a small area. This was incongruous with the composition and characteristics of a GRP panel. As I explain at [244(c)] below, a delaminated skin would not bulge out from the panel because of the stiffness of the skin. The fibreglass skins were not soft and flexible; they were hard and fairly rigid. Indeed Prof Nonhoff made the point that, if the honeycomb core were to give way, the upper skin would break rather than bend if loaded excessively, because of its stiffness (see also [215(b)] above). ⁵¹¹ The experts also agreed that any delamination which occurred would have been localised due to the presence of Z-strips (see [162] and [210(d)] above and [250] below). I therefore find it difficult to imagine that stepping on an area suffering from inner skin delamination could have caused that small area around one foot to dramatically deflect downwards. The stiffness of both the inner and outer skins, and the reinforcement provided by the Z-strips, would have limited the deflection underfoot. At most, if someone stepped on a panel which had widespread delamination, the entire panel would have curved downwards more noticeably. This was shown in the video of the core sampling exercise on 2 March 2010, during which Mr Carter jumped on the mock-up panel and the panel deflected downwards across its entire surface slightly. The core sampling team also walked and pressed down with the balls of their feet over the panels to detect cracking or crinkling sounds, and yet the video does not show any panels suddenly or dramatically dipping or sinking under their weight, though I could hear crinkling noises from the panels. There is not a single photograph of a panel deflecting substantially underfoot at a particular spot while being stepped or walked on.

219 Furthermore, none of the panels which allegedly deflected underfoot were removed and examined or tested, so there is no way of knowing how much they deflected; how much of this deflection was natural for a panel designed to the deflection limits specified in the Sub-Contract and how much was unnatural; and whether other factors (besides delamination) could have contributed to this phenomenon.

220 There also appears to have been another, different phenomenon – namely, an enduring deformation of the panels. Mr Attwood’s e-mail of 30 January 2010, for example, mentioned “sponginess” in the subject but attached the one photograph of a panel that appeared to be slightly depressed although there was nothing atop it (see [143] above). Mr Mackay also alluded to this possibility in his AEIC: ⁵¹²

221 Mr Mackay also referred to this at trial: ⁵¹³

However, I note once more that no photographs were taken of these “dry pools”. ⁵¹⁴

222 Prof Nonhoff also testified that it was possible for a panel to sag if the lower layer was delaminated, as shown in the photograph referred to at [143] above. ⁵¹⁵

223 I do not accept the sagging as evidence of delamination. There was no documentary evidence to back up the allegation of sagging, except for that one isolated photograph provided by Mr Attwood. The only other person who claimed to have experienced it was Mr Mackay. However, I did not find his evidence to be credible on this point. Mr Mackay gave the impression that a fairly small area of the panel (a “spot”, in his words; see [220]–[221] above) would exhibit sagging. As noted above this could have been photographed to show the same, but no photographs were taken. For the reasons I have stated at [218] above, I do not accept that the GRP panels would behave in such a way. Moreover, the sagging was not measured, so there is no way of knowing the severity of the problem. (I note that Mr Kolhatkar thought that the photograph showed a deflection of about 1mm or 2mm, which was “pretty normal variation” and “pretty normal for a panel in the course of its installation and its service” ⁵¹⁶ , though it is obvious from the photograph that the sagging depicted would have far exceeded 2mm.)

224 It was also not clear that the sagging depicted in that photograph was definitely caused by delamination. In the 2015 Tests, a fully-delaminated panel recovered to its original position fully after the load was taken off it, and Mr Wymond did not observe any deformation. ⁵¹⁷ Mr Wymond pertinently suggested that deformations on the surface of the panel could be due to a failure of the clips to align or engage properly. ⁵¹⁸ This is supported by photographs from Aedas’ report from the 3 September 2008 and 23 April 2009 factory visits, which shows that a panel can curve downwards at its ends if it is propped up in the middle. ⁵¹⁹ If the clips had not been aligned properly, then the non-aligned part of the panel may have protruded, creating the impression of a depression in the adjacent areas. Moreover, even if that one panel shown in the photograph was indeed sagging as a result of delamination, I would be inclined to attribute this to mishandling. The photograph taken by Mr Attwood shows that the panel was adjacent to a vertical panel, which increases the likelihood of it having been jumped on. Two ropes are clearly visible at the forefront of the photograph, which the workers would have used to traverse the panel. (I discuss the effect that walking and jumping on the panels could have had on the panels in greater detail at [298]–[312] below.)

225 Importantly, Mr Kolhatkar acknowledged at trial that BFG’s representatives had reported evidence of sagging, sponginess and deflection underfoot (he did not distinguish between these three terms). ⁵²⁰ The following excerpt from his re-examination is particularly illuminating: ⁵²¹

226 This, in my view, explains why Mr Kolhatkar maintained that delamination had occurred notwithstanding his view that the noises produced by the panels were not evidence of delamination (see [206] above). The reports of delamination from the BFG team onsite were based on phenomena other than the noises, particularly the panels “sponging” or deflecting underfoot. I therefore accept that some panels did deflect underfoot, although for the reasons stated at [218] above, I do not accept that this was as widespread as Mr Mackay suggested. I consider the extent of the delamination in greater detail at [248]–[254] below.

227 Kalzip also refers to evidence from MBS’ consultants, Arup and Aedas. The first of these is a non-conformance report (“NCR”) produced by Aedas dated 22 January 2010 following inspections on 8 and 20 January 2010. Annotations on the photographs within the report stated that delaminated GRP panels had been observed during the walk-up, including on leaves 10 and 13. ⁵²² One of the bullet points under “Design & Technical” stated: “The issue regarding the damaged delaminated GRP panels (currently leaves 10 and 13) needs urgent response from [Kalzip] / BFG.” ⁵²³ A photograph of the stepped roof area is annotated with the sentence, “During the walk up the roof damaged delaminated GRP panels observed in highlighted area.” ⁵²⁴ Three other photographs record that there were damaged, delaminated GRP panels on leaf 10 as well as leaf 13. ⁵²⁵

228 Secondly, there was a letter from Arup to Aedas on 19 May 2010, titled “Summary of status on the GRP cladding”. Under “Investigation of Delamination”, the letter stated: ⁵²⁶

229 Kalzip submits that “[t]he opinion of these third party building professionals must be given weight”. ⁵²⁷ However, BFG points out that it has never been submitted by Kalzip, nor does the evidence suggest, that MBS’ consultants carried out independent checks of the podium roofs. ⁵²⁸ Significantly, no representatives from Arup or Aedas gave evidence in the Suit, and there is no way for me to know what their assertions in the correspondence were based on. If they were based on the report of BFG’s and Kalzip’s witnesses, or if they likewise simply inferred delamination from the sounds emitted by the panel, they do not strengthen Kalzip’s case that delamination occurred. I note that representatives of Arup and Aedas were also present at the factory visits with Mr Carter (see [111] and [117] above). Although the report produced by Aedas on 22 January 2010 records that the inspection was attended by Mr Wong and Mr Mackay ⁵²⁹ , who were witnesses in the Suit, they did not discuss this in their AEICs nor were they questioned about it during trial. I am unable to see any signs of delamination from the photographs included in the report, and the consultants would not have been able to view the panels from below to conclude whether delamination in fact occurred. Moreover, the bulk of the report focuses on Kalzip’s non-conformances concerning the installation of the panels and their supporting structures, for example the lack of fasteners in the upper panel brackets; the removal of brackets from some panels; missing components; misalignment of parts; and other aspects of the installed roof which differed from the design intent and shop drawings. The reports of delamination receive comparatively little attention (four of 28 photographed defects) and appear to be confined to a few panels.

230 As for the letter dated 19 May 2010, this appears to have based the allegation of “extensive delamination” on Kalzip’s own investigation in March 2010. This may refer to the core sampling exercise which Kalzip undertook on 2 March 2010, which gave rise to concerns about variations in panel weight, but Kalzip expressly disavows reliance on that exercise as evidence of delamination (see [235]–[236] below). The same letter observes that “[a]lthough there have been several meetings a clear report on the cause and impact of the delamination has not been provided by [Kalzip]”.

231 I note that Aedas also issued NCRs on 1 March 2010 ⁵³⁰ and 5 March 2010 ⁵³¹ which referred to delaminated GRP roof panels. However, the latter NCR was expressly based on the 25 February site survey (see [154] above), which in turn was based on crunching sounds. In fact Mr Peter Morgan from Aedas, who was the “originator” of the NCRs, had attended that survey. There was no evidence as to how the findings in the NCR on 1 March 2010 were arrived at though it also referred to “site investigations / inspections of the MICE GRP panels carried out on 24-02-10 and 25-02-10”. Aedas also produced an NCR on 17 May 2010 stating that “the theatre panels [could not] be considered suitable for installation” in the light of the tests conducted on 14 May 2010 (see [81] above). ⁵³² However, given the problems I earlier identified with the Winwall tests and the site surveys (see [81]–[87] and [171]–[176] above), I do not accept Aedas’ NCR as evidence that the panels were non-compliant with the Sub-Contract structural requirements or that they delaminated. Moreover, all three NCRs were signed off by Mr Peter Morgan, who was not a witness in the proceedings and did not give evidence.

232 I agree with BFG ⁵³³ that the fire test samples suggest that any delamination which occurred was not widespread. This was a point made by Mr Wymond in his expert report. According to Kalzip’s four site surveys, it would appear that a large proportion of panels had delaminated. If this were so, one would expect to see a similar proportion of delaminated panels from the samples that were cut up for fire testing. However, out of the many cut samples used for fire testing – 249 samples according to Mr Wymond, 350 ⁵³⁴ or 390 ⁵³⁵ according to BFG – not one was reported to be delaminated. ⁵³⁶

233 Mr Wymond subsequently deleted this section of his report because it appeared to him from the rebuttal report of Dr Crowder, BFG’s fire expert, that many of the panels he referred to were reported to have delamination. ⁵³⁷ The relevant portion of Dr Crowder’s rebuttal report states: ⁵³⁸

234 As it turns out, however, Mr Wymond’s original point was in fact correct. As will be seen below, the fire experts came to the firm conclusion that the samples removed from the installed panels for fire tests were not delaminated at the time of their removal from the site. Delamination was only observed prior to testing, suggesting that the samples had delaminated sometime between removal from the site and testing (see [437]–[438] below). Unfortunately, this was not brought to Mr Wymond’s attention. I accept, on the basis of the fire experts’ evidence, that the fire test samples were not delaminated at the time of their removal from the site. This was supported by a well-documented report prepared by one Mr Kettle in the arbitration, which contained photographic evidence of the fire test samples being prepared for transportation to the testing houses. ⁵³⁹ In my view, this contradicts Kalzip’s allegation of widespread delamination.

235 During trial, Kalzip played a video showing core sampling of panels on 2 March 2010 (“the 2 March video”). ⁵⁴⁰ The video showed samples being cored from the visual mock-up (a scaled representation of the podium roof finishes to demonstrate the quality of the GRP panels ⁵⁴¹ ), the MICE building upper roof section and the casino building upper roof. The video captures the following:

(a) Two samples were cored from panels 2 and 3 of the visual mock-up. These showed no delamination, although Mr Carter could be heard saying that the core sample from panel 3 might have been “a little lighter” than panel 2. Mr Carter then jumped on the panels from which they were cored and remarked that these panels bore no sign of delamination or change in structural integrity.

(b) One sample was cored from leaf 16, panel 5 of the MICE building roof. The inner skin of the sample was totally delaminated; the upper skin was not delaminated. The perimeter of the cored hole emitted crinkling sounds when stepped on.

(c) One sample was cored from leaf 15, panel 9 of the MICE building roof. The panel had not delaminated and showed good resin saturation, but weighed 10.84kg/m2 against the mock-up panel’s weight of 14.76kg/m2. The perimeter of the cored hole showed no delamination propagation.

(d) Three samples were cored from leaf 13, panel 13 of the casino building roof. The inner skin of one sample was totally delaminated. The inner skin of another was partly delaminated. The inner skin of the third sample was almost totally delaminated; it delaminated completely upon some prying by Mr Carter.

(e) One sample was cored from leaf 12, panel 7 of the casino building. It showed no delamination.

236 I note that Kalzip expressly disavows reliance on this video as evidence of delamination. ⁵⁴² For completeness, I explain in this section why I would not, in any event, have considered it as evidence of delamination.

237 First, the very act of coring the panels could have induced the delamination. Kalzip’s expert, Mr Green, acknowledged that improper coring could possibly initiate delamination. ⁵⁴³ He played a video in court which showed that it was possible for a good panel to delaminate if it was cored using a drill with a blunt whole saw, because the drill would have to be pressed so hard against the panel that it might cause the panel to distort and delaminate. ⁵⁴⁴ Mr Wymond explained that the core sampling exercise in this case involved coring the panel at an angle, thereby inducing uneven loads to the inner skin, which could have resulted in a peeling failure of the core sample. Any pressure applied to the inner skin could “force it to separate from the honeycomb”. ⁵⁴⁵ Mr Wymond pointed out from the video that, although the circular sample itself had totally delaminated, the perimeter of the cored hole in the panel showed no visible delamination, suggesting that the delamination occurred as a result of the coring exercise itself ⁵⁴⁶ and also that it was possible for delamination to occur as a result of improper coring while leaving the perimeter of the hole intact ⁵⁴⁷ , for example if the central core is subject to torsions that do not occur to the outside of it ⁵⁴⁸ . Indeed, tests carried out by BFG at Kaskal on 16 February 2016 showed that a core sample could delaminate due to stresses induced through the coring operations, and that this did not equate to panel delamination. ⁵⁴⁹ Core sampling during the 2015 Tests also resulted in one core sample losing adhesion. ⁵⁵⁰

238 Mr Maurieschat agreed with this analysis. In his view, core sampling using a hole saw induced excessive vibrations in the hollow honeycomb cells. The vibrations induced debonding between the honeycomb core and the inner skin. ⁵⁵¹ A video of the coring exercise performed at Kaskal in February 2016 showed debonding occurring in the cells which had been broken by the saw. ⁵⁵²

239 Indeed, Mr Rade and Mr Flook – who both attended the core sampling exercise – took the view that Kalzip’s method of cutting would have damaged the panels and was an incorrect way of ascertaining delamination. ⁵⁵³ Mr Flook “could feel a lot of vibrations in the panel and could see that excessive force was being applied by the operatives to force the cutter through the panel”, and that even after the cutter had passed through the aluminium honeycomb core, “force was again required to cut through the back face of the panel, demonstrating that the back face was indeed bonded to the aluminium core”. Mr Rade observed that “excessive force was being applied to force a cutter through the panels”. ⁵⁵⁴ I therefore do not consider the core sampling exercise as evidence that the panels had delaminated.

240 Kalzip states that the panels manufactured for installation on the theatre building, which were stored in its warehouse, also delaminated. It further argues that this shows that delamination must have occurred before installation. ⁵⁵⁵ I set out the evidence regarding the delamination of the panels in storage before explaining why I do not accept this as evidence of widespread delamination.

241 First, the letter from Arup to Aedas dated 19 May 2010 (see [228] above) also stated that “[t]he extent of delamination was mapped in March 2010 and it was found that panels for the theatre in storage were also delaminated”.

242 Secondly, on 7 June 2010, Aedas and Arup conducted an inspection of the uninstalled theatre building panels stored in the Toll Warehouse. Arup e-mailed MBS representatives on 7 June 2010 attaching photographs from an inspection at the warehouse which allegedly showed a delaminated theatre panel (leaf 11, panel 14) in storage. ⁵⁵⁶ Mr Wong also attended this inspection and deposed that “[t]he tested panels exhibited signs of delamination”, but unfortunately did not state what “signs” these were and was not cross-examined about this. ⁵⁵⁷ (I note that he refers to this as the “7 June 2010 structural test” in his AEIC, but clarifies at para 47 that this was an “inspection” at the warehouse. This should not be confused with the 17 June 2010 structural test at [88] above.) Though Mr Wong’s AEIC refers to delaminated panels, the e-mail from Arup only refers to one delaminated panel, namely, leaf 11 panel 14 of the theatre building.

243 Thirdly, Prof Nonhoff gave evidence that he observed delamination in panels stored vertically in stillages in the storage facility in Singapore in June 2010. He came to this conclusion based on a number of visual tests and lifting the panels, which showed a buckling deformation of the inner face clearly indicating that delamination had occurred. He claimed to have seen deformations of 1mm–2mm out of the vertical plate (by which he probably meant “plane”). ⁵⁵⁸ His report included a photograph of an uninstalled panel, the bottom layer of which had completely delaminated when pulled by hand. Prof Nonhoff considered this to be evidence of delamination in that if the panel had been manufactured properly, it would have been impossible to delaminate it by hand. ⁵⁵⁹

244 I do not accept the foregoing as evidence that the GRP panels in storage suffered widespread delamination for the following reasons:

(a) Arup’s letter to Aedas dated 19 May 2010 expressed reliance on Kalzip’s own investigation in March 2010 (see [228]–[229] above). However, at that time, the view within Kalzip was that the sounds emitted by the panels were indicative of delamination. (Mr Wong would also likely have subscribed to this view.) I agree with Mr Wymond that any so-called delamination discovered in the panels could have been presumed by Kalzip on the basis of crunching or crinkling sounds, which did not necessarily signify delamination. ⁵⁶⁰ Since no representatives from Arup and Aedas gave evidence in these proceedings, it was impossible to know the basis of the letter, which could not be probed in cross-examination.

(b) Aedas’ and Arup’s inspection on 7 June 2010 also suffers from the same problem. In fact, the photographs of the panel appear to show people walking on the panel and marking out specific areas with tape, suggesting that the observation of “delamination” may have been based on sounds produced by the panel when walked on. Moreover, BFG submits that the photographs attached to Arup’s email on 7 June 2010 do not show any inner skin delamination, ⁵⁶¹ and I am indeed unable to identify any by sight. There are no photographs showing the delamination or of onsite personnel testing for delamination via other methods (for example, tap testing). ⁵⁶²

(c) Prof Nonhoff’s evidence is potentially the most persuasive evidence that delaminated panels were found among the theatre panels in storage. However, I regard his evidence with scepticism. A cored sample of one of the GRP panels was tendered in evidence and I observed that, as Mr Wymond and Mr Maurieschat said (see [162] above), the inner skin was not smooth but had a matted and uneven texture from the glass fibres. Moreover, the aluminium honeycomb was effectively sealed in by the two skins which formed a U-channel around the perimeter of the panel (see [46] above). Even if there was delamination between one of the skins and the honeycomb, this would not have resulted in the delaminated portion bulging out from the panel. In Mr Maurieschat’s words, “because of, first of all, the stiffness of the inner layer, you won’t see a bubble”. Moreover, the Z-strips would have prevented small areas of delamination from propagating. ⁵⁶³ I therefore find it difficult to believe that Prof Nonhoff would have been able to spot tiny “buckling deformations” of 1mm–2mm purely by sight, much less when the panels were still in their stillages. The panels were stored vertically within the stillages. Photographs of the stillages show that the panels were packed very closely together, suggesting that it would have been difficult to get a clear transverse view of the surface of the panels within each stillage. ⁵⁶⁴

(d) I also do not accept Prof Nonhoff’s evidence that extensive delamination occurred. As BFG points out, no survey was done of the panels at the Toll Warehouse, BFG was never invited to inspect the allegedly delaminated panels, and there are no records of the number of panels found to be delaminated. ⁵⁶⁵ No photographs were taken of the delamination or deformation of panels in storage, save one photograph of a panel with its inner skin separated. Prof Nonhoff asserted that this photograph “illustrates the inadequate bonding between the inner layer and the honeycomb core”. However, this panel was cut and its inner skin pulled apart by hand. Prof Nonhoff conceded during trial that it was possible to delaminate even a properly manufactured panel by hand, just that it would require “a lot of force”. ⁵⁶⁶ In the absence of measurement or documentation, it cannot be known how poor the adhesion between the honeycomb and the inner skin was. Moreover, he and Mr Wymond agreed that it was possible to pull the inner skin off a cored sample with both hands. ⁵⁶⁷ I also note Mr Wymond’s and Mr Maurieschat’s views that a peeling action would subject the inner skin to a load that it would not ordinarily have been subjected to. ⁵⁶⁸

(e) Surprisingly, despite the large volume of correspondence sent by BFG, there does not appear to have been any correspondence about the delamination of the theatre panels in storage. One would have thought that efforts to map the extent of delamination onsite would have been paralleled by efforts to do the same for the panels in storage. This would be all the more so after February 2010, by which time BFG had stated more than once that the installed panels had been damaged by workmen. The theatre panels were kept in the warehouse until April 2011 and Kalzip has not explained the total absence of any documented investigation into or examination of delamination in those panels. ⁵⁶⁹

245 BFG also makes the following points in its submissions:

(a) Kalzip’s position in these proceedings is “diametrically opposite” to the position it took in the arbitration with MBS and the correspondence preceding the arbitration. ⁵⁷⁰

(b) Kalzip has assembled a new cast of factual and expert witnesses for these proceedings (with the exception of Prof Nonhoff, who was one of Kalzip’s witnesses in the arbitration), which suggests that it engaged in “expert-shopping”. Besides changing its cast of expert witnesses since the arbitration, Kalzip also substituted two of the three experts it had appointed for this Suit in November 2015. BFG invites the court to draw an adverse inference from Kalzip’s sudden decision to substitute its experts. ⁵⁷¹

246 I have not placed any weight on these arguments in coming to my decision on the issue of delamination. As regards the first argument, the correspondence and pleadings that BFG has brought to my attention do not appear to deny that delamination occurred. Kalzip’s position was that the design of the GRP panels carried an inherent propensity to delaminate, and that MBS (rather than Kalzip) was to blame for choosing and approving that design. ⁵⁷² Kalzip did, however, repeatedly accept that delamination had occurred, which is consistent with its position on this issue in the present proceedings. ⁵⁷³ Although Kalzip may have denied liability on BFG’s part as a matter of law, I do not think that precludes Kalzip from taking the position in these proceedings that BFG was in breach of the Sub-Contract. Indeed that may very well be one reason that prompted Kalzip to reach a settlement with MBS in the arbitration.

247 As for the second argument, I decline to draw an adverse inference against Kalzip. The fact that Kalzip had changed its cast of factual and expert witnesses cannot, without more, logically ground the inference that delamination occurred; this is an issue of fact that remained to be tested by all the factual and expert evidence available before me. Moreover, the authorities cited by BFG in its submissions do not support the drawing of an adverse inference. They only suggest that, where the court becomes aware that expert shopping has occurred, it may make the admission of fresh expert evidence conditional upon disclosure of the previous expert’s report. ⁵⁷⁴ Indeed, in this case, the statements of Kalzip’s witnesses in the arbitration were all adduced in evidence. As for Kalzip’s substitution of two of its witnesses in November 2015, BFG could have, but did not, raise this issue then. ⁵⁷⁵ Had BFG then been able to persuade the court that there were concerns of expert shopping, it would have been possible to order the disclosure of the reports prepared by Kalzip’s two previously appointed witnesses (if any). However, no objection was raised at that stage and it would be inappropriate for me now to discount the evidence of Kalzip’s present witnesses on a mere suspicion that Kalzip’s substitution of witnesses was improper.

248 In conclusion, I reject Kalzip’s contention that there was “extensive delamination” onsite. The four site surveys, which were conducted on the premise that the crunching noises were proof of delamination, are not reliable proof of the existence or extent of delamination. As I have repeatedly noted above (see [15], [25], [102] and [221]), there is no primary evidence that the panels were delaminated when they were removed from the site. Even though Kalzip claimed that the panels were suffering from widespread delamination, there is no evidence of them removing specific panels for testing. Even after the panels were removed from the Project, they were stored in the Toll Warehouse. Kalzip had access to these panels and did in fact remove some of the theatre panels for the Winwall tests. (In fact, Kalzip claims damages for the costs of storing the theatre panels in the Toll Warehouse. ⁵⁷⁶ ) Notwithstanding that it had access to the panels, Kalzip did not take photographs of the MICE or casino panels (either while being installed or removed) to prove that they had delaminated, or send them for testing to establish inner skin delamination.

249 The evidence of some delamination came from the following:

(a) Prof Nonhoff’s observations during his June 2010 visit to the Project that some panels deformed underfoot, and photographic evidence of delamination in the panels which he cored (see [208]–[209] above). However, I have some doubts about the reliability of the evidence based on the coring exercise (see [210(c)] above). Moreover, only two panels were cored. Although Prof Nonhoff claimed that he saw deformations of large areas “on a lot of panels” ⁵⁷⁷ on both the casino and MICE building roofs, the precise panels were not identified or documented. I have also expressed my doubts and reservations regarding Prof Nonhoff’s evidence.

(b) Mr Mackay and Prof Nonhoff experienced panels deflecting underfoot (see [211] above). No photographs were taken. There is no evidence of how many or which panels exhibited this behaviour beyond the two core samples which Prof Nonhoff obtained. Mr Mackay did not say how many panels deflected underfoot.

(c) BFG’s internal correspondence in end January and February 2010 drew a distinction between the emission of sounds and the problem of delamination (see [206] above). Kalzip alleges that BFG concluded that delamination had occurred on both the casino and MICE building panels for reasons other than the sounds which were heard.

250 That some delamination occurred is supported by the view of BFG’s own expert, Mr Wymond. Notwithstanding that there was in his view a “complete absence of reports and diagnosis to support a claim of systemic delamination”, Mr Wymond took the view that “panel damage had occurred and this would include panel delamination due to mishandling, due to lifting, due to overloading of the panels, due to jumping on the panels and a combination of any one or more of these” [emphasis added]. ⁵⁷⁸ He also stated in his rebuttal report that Kalzip’s mistreatment of the panels “would have caused damage to [them] as observed through panels making crinkling and crunching sounds, which in isolated cases may have included localized delamination”. ⁵⁷⁹ However, such delamination would not have occurred over spans exceeding 500mm, due to the presence of Z stiffeners located at 500mm intervals connecting the top and inner skins. ⁵⁸⁰ As I noted at [162] and [210(d)] above, Prof Nonhoff and Mr Maurieschat also agreed that delamination occurred only in very localised and limited areas of the Project roofs. ⁵⁸¹

251 Given the dearth of direct evidence of delamination, it is not easy to determine exactly which and how many panels delaminated. An examination of the various e-mails sent by BFG only shows the following:

(a) On 7 December 2009, Mr Attwood wrote to others in BFG that Kalzip was aware of three panels with big areas of delamination (see [125] above). He must have been referring to the casino building, since installation on the MICE building had not yet begun. ⁵⁸² I do not accept this as evidence of delamination. This was reported by Kalzip, probably on the basis of sounds heard on the panels, which I have found were not evidence of delamination.

(b) On 11 January 2010, Mr Attwood e-mailed others in BFG that there were “around 6 places where delamination [had] taken place between front top face and aluminium honeycomb” (see [127] above). However, as I have said, this e-mail appears to allude to outer skin delamination, which is not the subject of Kalzip’s claim against BFG. Moreover, the six areas had been identified based on the presence of crunching sounds. ⁵⁸³ I therefore do not take this as evidence that six panels had inner skin delamination.

(c) On 18 January 2010, Mr Attwood repeated his report that there were six to seven places where delamination had occurred, the largest measuring around 700mm in diameter (see [129] above). Mr Attwood then said that this appeared to be a case of outer skin delamination, which is not in issue here, though he seemed unsure (see [130] above). The e-mails do not explain what these reports of delamination was based on, and I accept Mr Attwood’s evidence that they were based on the noises coming from the panels (see [164] above). I therefore do not take this as evidence that six panels had inner skin delamination.

(d) On 20 January 2010, Mr Attwood e-mailed others in BFG, saying that Kalzip had informally informed BFG about delamination of some panels after installation. BFG had “informally carried out” an “inspection of the panels” and identified six delaminated panels “at the peripheral area” in patches of approximately 0.5m by 0.5m (see [133] above). Again, this was probably referring to the same six panels and based on the sounds coming from the panels. I do not take this as evidence that six panels had inner skin delamination.

(e) On 27 January 2010, Mr Attwood reported to others in BFG that there were 20 delaminated panels on the MICE building and a further eight delaminated panels on the casino building (see [138] and [139] above). Mr Attwood explained that this was based on the panels producing a crunching sound when walked upon, which he assumed was evidence of delamination. I therefore do not take this as evidence that these panels had inner skin delamination.

(f) On 29 January 2010, Mr Kolhatkar e-mailed Dr Samer that “it [was] reported” that about 20% of the GRP panels had delaminated in areas of under 1m2. However, he expressed doubts about this conclusion, suggesting that there “may not be actual [delamination] but the sound of [aluminium honeycomb] during walking may be giving an impression of a debond” [emphasis added]. In fact, Kalzip was apparently unable to show Mr Premamoorthy “an actual incidence of the debonding” (see [140] above). Moreover, there is no evidence of how the 20% figure was derived and this was not put to Mr Kolhatkar during trial. I therefore do not take this as evidence that 20% of the panels had inner skin delamination.

(g) On 1 February 2010, the BFG inspection team went onsite to investigate the allegations of delamination. ⁵⁸⁴ That same day, Mr Attwood reported inter alia that there was inner skin delamination in small areas due to initial high point loads which were subsequently enlarged by foot traffic and heavy load forces due to installation of the panels (see [146] above). There was no indication of the extent of the inner skin delamination but reading his e-mail does not give the impression that it was widespread. I note that Kalzip’s own site survey of the casino roof (which I have not accepted) only marked 50 out of some 350 horizontal roof panels with alleged delamination.

(h) On 2 February 2010, Mr Kolhatkar e-mailed Mr Carter and said that about 20 panels on the casino building had delaminated but that panels on the MICE building showed no delamination signs and only “metallic noise coming out of [the aluminium honeycomb]” (see [147] above). By this time, Mr Kolhatkar had rejected the hypothesis that the sounds coming from the panels were proof of delamination and so the 20 panels must have exhibited other signs of delamination (see [206] above). BFG’s report following the site inspection of 3 February 2010 likewise reiterated that 20 panels on the casino building exhibited delamination (see [148] above). These e-mails could be said to be some evidence that 20 panels on the casino building had delaminated. Why they had delaminated is another matter.

(i) I should add that, although Mr Kolhatkar also told Dr Samer on 8 February 2010 that 60 panels on the casino building had to be repaired ⁵⁸⁵ , he was unable to explain what this figure was based on. That figure is not corroborated elsewhere. Mr Kolhatkar “[did not] have any reference on what was the criteria used by [his] site team to establish delamination” and had significant difficulty recalling how he had derived the figure or what objective evidence it was based on. ⁵⁸⁶ Nor is there evidence of such other signs of widespread delamination as would have caused BFG’s representatives to conclude that 60 panels delaminated. That is nearly double the number of panels that were found to emit crunching sounds during the 6 February survey two days earlier. ⁵⁸⁷

252 I therefore find that the delamination on the casino building was limited to 20 panels. This is on the basis of BFG’s internal e-mails, which would have been based on the site investigations undertaken by its team of trained personnel. BFG’s conclusion that 20 panels had delaminated was not based on the sounds being produced by the panels but on other phenomena, such as panels deflecting underfoot.

253 On the other hand, there is no reliable evidence of the extent of delamination on the MICE building. Though Mr Attwood sent an e-mail on 27 January 2010 stating that there were 20 delaminated panels on the MICE building, this was based on panels which exhibited a crunching sound when walked upon (see [138] above). His e-mail to Mr Anand on 6 February 2010 –around the time that BFG’s internal correspondence began distinguishing between the sounds emitted and delamination – does not mention any delamination on the MICE building. It refers only to the “large and uniform crinkling sound” on the MICE building, in contradistinction to delamination on the casino building. Mr Attwood stated that BFG had already found a solution to the delamination problem, but did not know what to do about the MICE panels – suggesting that the two problems were different. ⁵⁸⁸ Though there is an e-mail on 8 February 2010 from Mr Rade to Mr Kolhatkar which states that the MICE building panels have “patches of delamination” (see [150] above), Mr Kolhatkar’s email to Dr Samer just over an hour later clearly distinguishes the “delamination” on the casino building from the “sound of crumbling ALHC inside the panels while walking on the panels” on the MICE building. ⁵⁸⁹ An e-mail from Mr Kolhatkar on 11 February 2010 records that BFG’s position as of that date was that the casino building had delamination whereas the MICE building had merely the sound of aluminium honeycomb (see [152] above). I have also explained above why the evidence does not permit me to conclude that there was delamination on the panels in storage which were to be installed on the theatre building (see [244] above). Kalzip has therefore not discharged its burden of proving delamination on the MICE building or of the panels in storage on a balance of probabilities.

254 I now turn to consider the cause of the delamination, if any.

255 Assuming delamination occurred, was it for BFG to prove that it had manufactured the panels properly and the delamination had been caused by Kalzip’s mishandling, or for Kalzip to prove the converse? The parties take contrary positions on this issue.

256 Kalzip submits that the burden lies on BFG to establish, as a defence, that Kalzip mishandled the panels and caused them to delaminate. If it fails to do so, “it must follow that the only plausible explanation for the delamination is the defective manufacturing by BFG”. ⁵⁹⁰ BFG, on the other hand, submits that “the legal burden is on Kalzip to prove that BFG’s manufacturing process caused delamination”. Only when Kalzip “discharges its evidential burden by logically demonstrating with the evidence that the manufacturing process is the prima facie likely cause of delamination” does the “tactical burden” then shift back to BFG to disprove this on a balance of probabilities. ⁵⁹¹

257 It is helpful to consider the approach of the Court of Appeal in the case of Anti-Corrosion Pte Ltd v Berger Paints Singapore Pte Ltd and another appeal [2012] 1 SLR 427 (“Anti-Corrosion”), which BFG cited. In that case, the respondent was a paint manufacturer who had supplied paint to the appellant, a subcontractor, for use in a building project. Various internal surfaces of the building which had been painted with that paint subsequently developed serious discolouration and the subcontractor had to repaint those areas. It sued the paint manufacturer for its losses. One of the main issues in dispute was whether latent defects in the paint supplied had caused the discolouration.

258 The Court of Appeal found that the legal burden was on the appellant sub-contractor to prove that defects in the paint or its unfitness led to its discolouration. It was common ground between the parties that there were only three possible causes of the discolouration: (1) defects in the paint’s formulation, (2) the condition of the internal surfaces being painted and (3) poor workmanship in applying the paint. The subcontractor adduced sufficient evidence to eliminate surface conditions and poor workmanship as causes of the discolouration, leaving defects in the paint or its unfitness as the probable cause (at [37]). At this stage, “Once the evidence logically demonstrated that defective paint was prima facie the likely cause of the discolouration, the tactical burden shifted to the Respondent to show that this was not correct on a balance of probabilities.” The manufacturer could, for example, have adduced evidence that no complaints were received from other customers in relation to paint sold from the same batches. However, it did not do so. The prima facie likelihood that the discolouration was caused by defective or unfit paint was therefore unrebutted. It was also “reinforced” by evidence from the subcontractor’s expert witness. The Court of Appeal said of her evidence, at [36]:

259 The Court of Appeal therefore found that the paint discolouration was more likely than not caused by defects in the paint.

260 In this case, Kalzip clearly bears the legal burden of proving both that the panels delaminated and that they did so because of BFG’s defective manufacturing. (This is similar to Anti-Corrosion, where the subcontractor likewise bore the legal burden of proving that defects in the paint or its unfitness caused its discolouration.) Both the fact of delamination and BFG’s causation of the same are essential to Kalzip’s claim for breach in contract (see s 103 of the Evidence Act (Cap 97, 1997 Rev Ed) (“the Evidence Act”) and SCT Technologies Pte Ltd v Western Copper Co Ltd [2016] 1 SLR 1471 (“SCT Technologies”) at [17]). If BFG manages to establish that the panels delaminated because of the way in which they were subsequently handled and stored, rather than because they were manufactured poorly, it will not have proved a “defence” as such, but rather will have disproved an element of Kalzip’s claim. The legal burden of proving both the fact and cause of delamination therefore rests on Kalzip from start to end.

261 By contrast, the evidential burden to produce evidence, which is “not so much a burden of proof as it is a ‘tactical initiative which must be taken by a party if he is to succeed’” [internal citations omitted] (SCT Technologies at [18]), may shift back and forth. The following passage from Britestone Pte Ltd v Smith & Associates Far East, Ltd [2007] 4 SLR(R) 855 at [60] eloquently articulates the interaction between these two concepts:

262 In this case, I accept that if Kalzip proves as a fact that the panels had delaminated, the tactical burden shifts to BFG to produce evidence to show that the panels delaminated because of some action or error not attributable to BFG. BFG has identified various such acts, for example, Kalzip’s failure to store the panels appropriately; its failure to put in place a proper installation process; using the panels as working platforms; and so on. If BFG fails to prove that any of these could have caused delamination, then by process of elimination it will be more likely than not that the panels delaminated because they were not manufactured to the requisite standard. It would not be reasonable to require Kalzip to further prove that it did not mishandle the panels in other ways not specified by BFG, since that would require it to prove a negative. It would also be inordinately onerous to require Kalzip to positively prove that the panels were manufactured defectively or pinpoint the stage of manufacture which went wrong, since the details and documentation of that process are firmly within BFG’s knowledge and possession. If Kalzip adduces sufficient evidence to discredit BFG’s allegations that Kalzip or some other party was responsible for the delamination, the tactical burden then falls on BFG to rebut the prima facie likelihood that it is to blame. This is again similar to Anti-Corrosion: once other causes of discolouration had been eliminated on the evidence, the tactical burden fell on the paint manufacturer to show that the paint was not defective or unfit.

263 Before I analyse the causation issue, I state for the avoidance of doubt that I have disregarded Prof Nonhoff’s evidence on structural issues, such as the adequacy of the support rail system and whether it could have contributed to delamination, and the possibility of twisting and bending of the panels during installation. ⁵⁹² Counsel for BFG took objection to these aspects of Prof Nonhoff’s evidence because Prof Nonhoff was presented as a GRP expert, not a structural expert. Counsel for Kalzip accordingly confirmed that Kalzip was content to look to Mr Green as its structural expert and that the court might disregard Prof Nonhoff’s evidence insofar as it related to structural issues. ⁵⁹³ I have therefore limited my consideration of Prof Nonhoff’s evidence to the GRP panels alone, and not its supporting structures.

264 With that, I turn to consider BFG’s allegation that Kalzip’s acts caused the delamination.

265 One of BFG’s contentions is that delamination can only have occurred onsite as a result of mishandling, because the panels were certified not to be delaminated when they left the factory.

266 Kalzip appointed a third-party consultant, Loxon, to serve as its onsite quality control inspectors. Kalzip identifies Loxon as Loxon Wandset Inc whereas BFG identifies Loxon as Loxon Philippines Inc ⁵⁹⁴ , but there is no dispute about the identity of the company and I refer to it as “Loxon”. Three personnel from Loxon were based at BFG’s Philippines factory; according to Mr Premamoorthy they were there “from time to time” but according to Mr Zeeyad they were there “throughout the entire manufacturing period”. ⁵⁹⁵ After checks and inspections by BFG’s quality control personnel during and after the manufacture of the GRP panels, Loxon carried out inspections and verifications of the panels’ quality and signed off on quality control records. These included documents titled “quality control sheet”, “visual check sheet for gelcoat side” and “visual check sheet for lamination side”; one of each of these documents was produced per panel. Mr Bridger confirmed that all the panels produced at BFG’s factory were inspected by Loxon before shipping to Singapore and that Loxon carried out visual and dimensional inspections. ⁵⁹⁶

267 After the panels were de-moulded, they would be visually inspected for any humps, protruding fibres, dry patches and/or signs of de-bonding. The Visual Check Sheet for Lamination Side prompted the inspector to check for delamination, without stating how this was to be done. Kalzip submits that the test was purely visual. ⁵⁹⁷ However, both Mr Premamoorthy and Mr Zeeyad stated that the “Visual Check Sheet for Lamination Side” required Loxon personnel to perform a tap test on the underside of the panel to check for delamination, although the document itself did not stipulate such a requirement. ⁵⁹⁸ This involved using a wooden mallet to tap the skin while listening for sounds that might indicate some hollowness, which could suggest a lack of bonding. This was the only way of identifying delamination, since it could not be observed visually. ⁵⁹⁹ Mr Zeeyad had witnessed such tests being performed while at the factory. ⁶⁰⁰ The details of this inspection were then recorded in the Visual Check Sheet for Lamination Side. ⁶⁰¹ I accept Mr Premamoorthy’s and Mr Zeeyad’s evidence, and the quality control documents signed off on by Loxon, as proof that the panels were in good condition (including no delamination) at the time that they left BFG’s factory. Loxon was an independent third-party inspector and there is no evidence that Loxon protested the quality of the panels or raised any objections about the manufacturing process.

268 That said, I do note that Kalzip’s case is not that BFG breached the Sub-Contract by supplying delaminated panels. Its case is that BFG supplied panels which deflected excessively under the loads they were required to bear under the Sub-Contract. ⁶⁰² Delamination is only relevant insofar as panels which delaminated would have breached the deflection limits of the Sub-Contract (see [99] above). To establish breach, it need not be shown that the panels had already delaminated by the time they left the factory. Provided there was no mishandling or misuse of the panels by Kalzip, it need only be shown that the panels delaminated onsite under loads which they ought to have been capable of bearing.

269 BFG submits that I should draw an adverse inference against Kalzip for not calling Loxon personnel to give evidence in the proceedings. ⁶⁰³ I decline to do so. It was BFG, not Kalzip, which relied on the Loxon check sheet to establish that delamination had only occurred after the panels left the factory. Moreover, given what I have said in the foregoing paragraphs, I do not consider that the outcome of the Loxon tests would make or break Kalzip’s case, so there is nothing suspicious or unreasonable about Kalzip’s decision not to call Loxon personnel as witnesses.

270 I now turn to BFG’s allegations of mishandling and misuse of the panels by Kalzip. First, BFG submits that Kalzip mishandled the panels in the following ways:

(a) by failing to store them appropriately onsite;

(b) by failing to put in place a proper installation process or system;

(c) by placing and/or storing heavy materials atop the panels; and

(d) by using the panels as working platforms for installation.

271 Mr Green’s view was that BFG had simply not supplied any positive evidence to demonstrate that the delamination was caused by any mishandling or other wrongdoing on Kalzip’s part. ⁶⁰⁴ Generally, he considered that there was no reason to believe that the panels which exhibited delamination had been treated or handled any differently to those which did not delaminate. Moreover, some of the panels in storage had delaminated despite never having been installed. From this he concluded that delamination could not have resulted from storage, handling and installation methods, but must have arisen from shortcomings in the manufacturing process. ⁶⁰⁵

272 However, Mr Green acknowledged that his belief that the panels were all subject to an identical installation process was based purely on a documentary review, and was not based on actual onsite installation, which he did not witness. ⁶⁰⁶ He also agreed that, insofar as the manufacture of the panels was concerned, that was something that Prof Nonhoff would pursue, and not he himself. ⁶⁰⁷

273 Mr Wymond’s position regarding the alleged mishandling was that Kalzip had not supplied any evidence that it had not mishandled the panels. He did not positively assert that the GRP panels were damaged by mishandling, as “very limited information” was available in relation to panel installation. Other than photographs taken during the installation process, there was no evidence either way of correct or incorrect handling during installation or storage. For example, there were no procedures or records addressing worker access, fall arrest lines, material loads or manner of storage. However, Mr Wymond thought that the GRP panels could in theory have been damaged by “installation processes that are normally routine” due to their large size. His view was not that Kalzip had definitely caused delamination, but that Kalzip had not shown sufficient evidence to disprove that possibility: “Kalzip/Corus have not provided evidence that they handled the [GRP] panels in a manner that could guarantee that they did not damage the panels”. ⁶⁰⁸ He thought it unlikely that panel damage was attributable to BFG, since the panels which had left BFG’s factory had all been checked for quality control. ⁶⁰⁹

274 Given my foregoing remarks about the evidential burden, I do not agree with Mr Wymond’s approach to the question of whether Kalzip mishandled the panels. The onus was on BFG to adduce evidence to prove that Kalzip had done so.