Contek Pty Ltd v Mossop Group Pty Ltd

[2024] SADC 1

DISTRICT COURT OF SOUTH AUSTRALIA

(Civil)

CONTEK PTY LTD v MOSSOP GROUP PTY LTD

[2024] SADC 1

Judgment of her Honour Judge Thomas  

15 January 2024

CONTRACTS - BUILDING, ENGINEERING AND RELATED CONTRACTS - PERFORMANCE OF WORK

CONTRACTS - BUILDING, ENGINEERING AND RELATED CONTRACTS - THE CONTRACT - CONSTRUCTION OF PARTICULAR CONTRACTS AND IMPLIED CONDITIONS - VARIATIONS

CONTRACTS - BUILDING, ENGINEERING AND RELATED CONTRACTS - THE CONTRACT - CONSTRUCTION OF PARTICULAR CONTRACTS AND IMPLIED CONDITIONS - DETERMINATION OF COST

EQUITY - GENERAL PRINCIPLES - MISTAKE - EQUITABLE REMEDIES

The Applicant (Contek) carried out concreting works for the Respondent builder (Mossop) for two unrelated commercial building projects under bespoke subcontracts made in late 2015 for the Aldi project and 2016 for the Lifecare project respectively. Disputes arose during the course of both projects over numerous variation claims. Proceedings were instituted in June 2018 by Contek claiming damages for unpaid variation claims. Mossop counterclaimed entitlement to set off back charges for various items.

The first part of the trial was adjourned for Contek to amend to introduce a new cause of action for rectification of the Lifecare subcontract and in the further alternative, claims for misleading and deceptive conduct and unconscionability under ss 18, 20 and 21 of the Australian Consumer Law for its extra steel variation claims.

Ultimately, the Court was required to determine 13 discrete claims involving a wide range of factual and evidentiary issues. The most significant and complex claims concerned Contek’s variation claims for extra concrete and steel for the Lifecare project.

Questions considered as to the proper basis of assessing and valuing variation and back charge claims, the existence and scope of instructions and directions to vary works, the contractual process for claiming variations and non-compliance with notice provisions and betterment. Observations made as to the proper basis for fact finding, whether unpleaded claims and defences should be permitted to be agitated at trial and the inferences arising from failure to call relevant witnesses or adduce relevant evidence from testifying witnesses.

Held:

1.    Judgment for Contek in the amount of $40,655.18 ex GST for its variation claims V2, V6 and V8 (extra concrete) net of the amounts assessed and paid.  The fullest and best evidence of the additional Helix fibre concrete required is the volume of concrete supplied to site as proven by the Hanson delivery dockets less a fair and reasonable allowance for the volume of standard concrete measured by the concrete drawings as adjusted for volumes for joints, infills, fillings and 160mm slabs as measured by the project quantity surveyor.

2.    Judgment for Contek on its claim for rectification of the Lifecare subcontract to list in Appendix D revision 00 for structural drawings S04, S05 and S23.

3.    Judgment for Contek in the amount of $27,007.66 ex GST for its Lifecare project variation claims V7 and V9 (extra steel reinforcing) net of the amount assessed and agreed to be paid. There was a material change between the Tender and Contract Drawings as to the volume of steel reinforcing required for the planter box edges to the first and second floor slabs. The OneSteel variations to its supply contract with Contek are a fair and reasonable basis for valuing the variation claims.

4.    As for Mossop’s Lifecare project back charge claims, judgment for Mossop in the amounts of $4,500,00 ex GST for claim B5 (Patch & Caulk – Balcony Works). $4,359.50 ex GST for claim B11 (Basement Repairs) and $10,000 ex GST for claim B13 ( Partial Rectification to Basement Works).  Mossop’s back charge claim B10 (TC Formwork to Beam Above Ramp) is dismissed.

5.    Judgment for Contek in the amount of $5,690.00 for its Aldi project variation claim B2.0 (cast-in angles & slab redesign) net of the amount assessed and agreed to be paid. 

6.    Mossop’s back charge claim B1 (absence from the Aldi project site) is dismissed.

7.    As to the disputed settlement amounts, Mossop’s contention that the parties’ settlement agreement covers the entirety (and not just the disputed component) of amounts claimed by Contek for its Aldi variation claims B1.0 (cancelled concrete pour) and B3.1 (pylon sign pad footing) is rejected. Judgment for Contek in the amount of $4,192.50 ex GST for claim B3.1 (pylon sign pad footing). Although Contek’s claim B1.0 (cancelled concrete pour) was not settled, it is dismissed as unproven.

Australian Competition and Consumer Act 2010 (Cth), Australian Consumer Law sch 2, ss 18, 20, 21, referred to.

Simic v NSW Land and Housing Corporation (2016) 260 CLR 85, applied.

Australasian Performing Right Association Ltd v Austarama Television Pty Ltd [1972] 2 NSWLR 467; Bellgrove v Eldridge (1954) 90 CLR 613; BCI Finances Pty Ltd (in liq) v Binetter (No 4) (2016) 348 ALR 227; Commonwealth v Jennings Construction Ltd [1985] VR 586; Demagogue Pty Ltd v Ramensky (1992) 39 FCR 31; Diploma Construction Pty Ltd v Marula Pty Ltd [2009] WASCA 229; Ho v Powell (2001) 51 NSWLR 572; Jones v Dunkel (1959) 101 CLR 298; Mann v Paterson Constructions Pty Ltd (2019) 267 CLR 560; Maralinga Pty Ltd v Major Enterprises Pty Ltd (1973) 128 CLR 336; Mount Bruce Mining Pty Ltd v Wright Prospecting Pty Ltd (2015) 256 CLR 104; NRM Corporation Pty Ltd v ACCC [2016] FCAFC 98; Ritz Hotel Ltd v Charles of the Ritz Ltd (No 7) (1987) 14 NSWLR 104, considered.

CONTEK PTY LTD v MOSSOP GROUP PTY LTD
[2024] SADC 1

PART A: INTRODUCTION

PART B: THE TRIAL

PART C: THE EVIDENCE

The Witnesses Generally

The Witnesses Called

Mr Apostolakos

Mr Stringer

Mr Orlovic

Mr Mossop

Mr Lalli

Mr McFarlane

Witnesses Not Called

Mr Kemp

Mr Barone

Mr Zilic

Mr Tziortzis

PART D: LIFECARE PROJECT – TOPIC 3 - EXTRA CONCRETE

The Dispute – $58,008.38 ex GST

The Variation Claims

Claimed Additional Volumes

The Parties’ Contentions

The Pleadings

The Parties’ Contentions at Trial

The Issues to be Determined

The Evidence

The Topping Slab Works

Mossop’s Assessment

Set-Down Measurements

The Alexander Symonds Survey

Evidence of Inconsistency in Deltacore Floor

QS Assessments

The Issues Answered

Issue 1:   Was there an instruction or direction constituting a variation?

The Implications of any Answer

The Parties’ Cases

Change in Concrete Mix

On-site Direction to Vary

Breakouts

Issue 2: Are these variation claims contractually barred?

The Subcontract Variation Provisions

Consideration

Conclusion

Issue 3:  Is the Alexander Symons survey result binding?

Consideration

Conclusion

Issue 4:  Was Contek’s standard concrete allowance adequate?

The Parties’ Contentions

Evidence of Take-offs

10% Wastage Allowed

Allowance for Joints, Infills or Fillings

Allowance for 160mm Slabs

Allowance for 400mm Slabs

Tender or Contract Drawings?

Conclusion

Issue 5:  What is a fair and reasonable measure for any additional concrete?

Consideration and Conclusion

PART E: LIFECARE PROJECT – TOPIC 4  - EXTRA STEEL

The Dispute – $27,007.66 ex GST

The Variation Claims

Mossop’s Assessment

The Lifecare Subcontract

The Parties’ Contentions

The Issues

Issue 1: Should the Lifecare subcontract be rectified?

Relevant Legal Principles

The Evidence

Conclusion

Issue 2: Did Mossop mislead Contek about the Contract Drawings?

Issue 3: Was there any material change between the Tender and Contract Drawings?

The Drawings

Changes to the Reinforcing

Conclusion

Issue 4: What is the fair and reasonable value of the variation claimed?

OneSteel Documents

Conclusion

Issue 5: Are these variation claims contractually barred?

Consideration

Conclusion

Overall Conclusion

PART F: LIFECARE PROJECT – TOPIC 7 – BACK CHARGE CLAIMS

The Disputes – Back Charge Claims B5, B10, B11 & B13

B5 – Patch & Caulk Balcony Works Back Charge - $10,990.90 ex GST

B10 – TC Formwork to Beam Above Ramp – Back Charge - $3,837.00 ex GST

B11 – Basement Repairs – Back Charge - $4,359.50 ex GST

B13 – Partial Rectification of Basement Works – Back Charge - $12,000.00 ex GST

The Issues

Inadequate Fall on Spoon Drains

Direction to Pour in Wet Weather

Betterment

Conclusion

PART G: ALDI PROJECT – TOPIC 10 – CAST IN ANGLES

Disputed Value - $5,760.00 ex GST

PART H: ALDI PROJECT – TOPIC 11 – ABSENCE FROM SITE

Disputed Back Charge - $9,626.36 ex GST

The Christmas Closure

The Relevant Program

Conclusion

PART I: SETTLEMENT DISPUTE

Issues in Dispute – Aldi Project Variation Claims B1.0 and B3.1

PART J:  FORM OF JUDGMENT AND JUDGMENT SUM

PART K:  COSTS

PART A: INTRODUCTION

1. This proceeding concerns disputed variation and back charge claims under two subcontracts between the same parties for concrete works for unrelated building projects.  One project concerns a two-storey aged care facility in Joslin known as the Lifecare Roselin Court Stage 1 (Lifecare) Project.  The second concerns the Aldi supermarket at Berri (Aldi) Project.

2. The Applicant, Contek Pty Ltd (Contek), is a building contractor specialising in the supply of civil and concreting works for commercial projects.  The Respondent, Mossop, carries on business as a licensed builder and was the principal building contractor for the Lifecare and Aldi Projects.

3. The Lifecare subcontract[1] was in writing and made in October 2016 for concrete works involving the supply of labour and materials for the footings and the slabs for the basement, ground, first and second floors and the stairs for the Lifecare Project in consideration of a fixed lump sum subcontract price of $1,092,180.00 ex GST.[2]

   [1]    Exhibit A1 page 182.

   [2]    $1,201,398.00 inc GST.

4. The Lifecare subcontract works the subject of dispute were carried out in late 2016 and 2017.

5. The Aldi Project was first in time. The Aldi subcontract[3] was in writing and made in October 2015. It concerned a lesser scale of concrete works for development of a supermarket involving the supply of labour and materials for the concrete slab and footings of the main supermarket building, with in-situ retaining wall footings and walls and external concrete pavement in consideration of a fixed lump sum price of $546,500.00 ex GST.[4]

   [3]    Exhibit A8 page 5.

   [4]    $601,150.00 inc GST.

6. The Aldi subcontract works were carried out in late 2015 and early 2016.

   7Proceedings were instituted in June 2018 claiming Contek was entitled to be paid by Mossop for unpaid invoiced amounts for both of the Lifecare and Aldi subcontract works as allegedly varied.  Mossop counterclaimed entitlements to set off back charges for various items. The parties narrowed some of the issues in dispute during the interlocutory stages of the proceeding and during the course of the trial. 

   PART B: THE TRIAL

7. The trial was heard in parts in November 2021 and in September, November and December 2022.  The first part took place over two and half days and was adjourned following Contek’s application to amend its claim to introduce causes of action for rectification of the Lifecare subcontract, misrepresentation and unconscionable conduct as regards Contek’s claimed variations for extra steel for the Lifecare project.[5]

   [5]    See Topic 4 below.

8. The second part of the trial proceeded over seven days on revised pleadings that do not define the real issues in dispute with clarity.[6] Further concessions were made by both parties during the adjourned trial, further reducing the scope of the issues to be determined by the Court and the quantum in dispute.  By the end of the trial the parties agreed it was only necessary for the Court to determine the discrete claims set out in the following table.

   [6]    Amended Third Statement of Claim dated 1 March 2022 (FDN 66) (the Claim); Amended Third Defence and Counterclaim dated 5 April 2022 (FDN 67) (the Defence and Counterclaim); Reply to Third Defence and Second Defence to Counterclaim (Revision 3) dated 21 June 2022 (FDN 72) (the Reply and Defence to Counterclaim).

   Table 1

No.	Description	Claimed Value ex GST	Agreed Value ex GST	Disputed Value ex GST
LifeCare Project
V2	Extra Concrete – Ground Floor	$36,217.97	$4,977.00	$31,240.96
V6	Extra Concrete – First Floor	$26,973.24	$13,250.59	$13,722.65
V7	Extra Steel – First Floor	$14,031.68	$527.85[7]	$13,503.83
V8	Extra Concrete – Second Floor	$18,590.52	$5,545.76	$13,044.77
V9	Extra Steel – Second Floor	$14,031.68	$527.85[8]	$13,503.83
B5	Patch & Caulk – Balcony Works	-$10,990.90	Nil	-$10,990.90
B10	TC Formwork to Beam Above Ramp	-$3,837.00	Nil	-$3,837.00
B11	Basement Repairs	-$4,359.50	Nil	-$4,359.50
B13	Partial Rectification to Basement Works	-$12,000.00	Nil	-$12,000.00
Total	$78,657.69	$23,773.35	$53,828.64
Aldi Project
B2.0[9]	Cast-in Angles & Slab Redesign	$14,890.00	$9,130.00	$5,760.00
B1	Absence from Site	-$9,626.36	-$9,626.36
Total	$5,263.64	$9,130.00	-$3,866.36
Grand Total	$83,921.33	$32,903.35	$49,962.28

[7] See [348] below.

[8] Ibid.

[9]    Sometimes referred to as V2.0.

1. As can be seen from the disputed amounts in Table 1 above, the complexity and number of the issues ultimately in dispute and the litigation costs involved were disproportionate to their value from the outset.

2. It is convenient to determine the claims before the Court in the way they were grouped and presented by project and ‘topic’. 

   ·The most significant claim is Contek’s variation claims for extra concrete for the Lifecare Project (V2, V6 and V8), referred to as Topic 3. 

   ·Next in significance is Contek’s variation claims for extra steel for the Lifecare Project (V7 and V9), referred to as Topic 4.

   ·Mossop’s back charge claims for patching and caulking works (B5), formwork to the beam above the ramp (B10), basement repairs (B11) and partial rectification and repairs (B13) for the Lifecare Project were part of Topic 7.

   ·Contek’s variation claim for cast-in angles and slab redesign for the Aldi Project (B2.0 or V2.0) was referred to as Topic 10.

   ·Mossop’s back charge claim for Contek’s absence from site for the footings pour (B1) was referred to as Topic 11.

3. Contek prepared an aide memoire in the course of the trial summarising the impact of the parties’ agreed and differing positions as to the disputed variation and back charge claims on the adjusted subcontract sums allegedly due net of payments made by Mossop (either to Contek or into Court) under each of the Lifecare and Aldi subcontracts. This aide memoire was in the form of a spreadsheet that underwent a number of iterations (both as MFI A12 then MFI A19) to which Mossop took various objections as to its accuracy.  The dispute between the parties was made all the more difficult because of their inconsistent use of GST exclusive and inclusive figures.

4. In the parties’ written closing submissions, Contek relied on a final iteration of MFI A19.  In response, Mossop relied on its own summary for each project (Tables 1 and 2) and full project summaries (Appendix 1).  Whilst there was a significant degree of common ground, despite the Court urging the parties to agree a single form of spreadsheet both during the trial and after oral submissions were made, the parties were unable to do so.   

5. It was at this stage of the proceeding that a further dispute arose between the parties about what had been agreed in resolving a number of variation and back charge claims during the trial.  This led to two further short hearings and further affidavit evidence being filed.  As a result, the Court is required to determine a further dispute about the parties’ alleged agreement concerning two further variation claims for the Aldi Project as set out in Table 2 below.  The conceded values are the disputed amounts shown in the aide memoires MFI A12 and MFI A19 as a result of the concession made by Contek’s counsel that it would abide by the Court’s determination of this dispute and not press the balance of its claim that it forwent in the settlement agreement.[10] 

   Table 2

   [10] T851.9-.10.

No.	Description	Claimed Value ex GST	Conceded Value ex GST	Disputed Value ex GST
Aldi Project
B1.0[11]	Cancelled Concrete Pour	$6,640.00	-$2,123.45	$4,516.55
B3.1[12]	Pylon Sign Pad Footing	$5,151.36	-$958.86	$4,192.50

[11] Sometimes referred to as V1.0.

[12] Sometimes referred to as V3.1.

PART C: THE EVIDENCE

1. The tender book comprised 13 volumes following orders made before the first part of the trial that it be compiled by topic of dispute.  This led to significant duplication between the volumes, and a well-justified complaint by Contek that the exercise was unhelpful and added complexity and difficulty in preparing and conducting the trial.  Contek’s counsel expressly reserved Contek’s rights in terms of costs on the first day of trial.[13] 

   [13] 15 November 2021, T2.9-3.17.

2. Each volume of the tender book was accompanied by a lengthy ‘narrative’ that served as a commentary on the relevant topic from Mossop’s point of view as well as an index to the documents relied on.  The narratives were in the nature of submission and the Court was invited to treat them as part of both Mossop’s opening and closing submissions. Although they were largely repetitive of Mossop’s closing written submissions, there were some material differences reflecting shifts in Mossop’s case over time in long running proceedings.

3. Both parties relied on lengthy written closing submissions which were supplemented orally.  Contek objected to Mossop’s closing written submissions reading like an expert’s report, with detailed drawings marked up with notes and accompanying commentary and annexures that were not tendered at trial or put to any witnesses.  Contek’s objections were not unreasonably made and the Court, as it is obliged to do, has reviewed both Mossop’s submissions and the documentary evidence carefully, bearing in mind the pleaded issues in dispute and the fundamental principles concerning fact-finding.

4. In this regard, much was said by both parties about the other’s failure to prove elements of their case or call witnesses who could have given evidence about relevant facts. Not only were some witnesses not called and their absence unexplained, but some of the witnesses who were called were not questioned on topics that they could have given evidence about that would have assisted the Court resolve some issues.  Taking a generous view, in part this was the product of the disproportion between the value of the claims in dispute and the costs of litigation and each party doing its best to prove its claims as economically as could be done.

5. In determining the issues in this case, the Court has borne in mind the following principles.

6. This Court in deciding facts according to the civil standard of proof must decide what are the probabilities on the evidence before the Court and where the evidence is limited and unsatisfactory, whether it is an appropriate basis on which to reach a reasoned conclusion.  It is in dealing with this second issue that the Court is to have regard to the ability of the parties, particularly the party bearing the onus of proof to lead evidence on a particular matter, and the extent to which they have in fact done so.[14]

   [14] Ho v Powell (2001) 51 NSWLR 572 at [14]-[15].

7. It is also pertinent in face of the many Jones v Dunkel objections taken in this case to emphasise that the absence of a witness is “only significant where the evidence which such a person is expected to give would (not might) elucidate a particular matter in issue.”[15] As explained by the High Court in Jones v Dunkel:[16]

   [A]ny inference favourable to the plaintiff for which there was ground in the evidence might be more confidently drawn when a person presumably able to put the true complexion on the facts relied on as the ground for the inference has not been called as a witness…

   [15]  BCI Finances Pty Ltd (in liq) v Binetter (No 4)(2016) 348 ALR 227 at [127] per Gleeson J.

   [16] (1959) 101 CLR 298 at 308 per Kitto J.

1. It follows that there first must be some existing basis in the evidence to support the inference one party contends should be drawn before the absence of evidence from the opposing party is significant.  As clarified in Cross on Evidence:[17]

   Thirdly, the rule only applies where a party is “required to explain or contradict” something.  What a party is required to explain or contradict depends on the issues in the case as thrown up in the pleadings and by the course of evidence in the case.  No inference can be drawn unless evidence is given of facts “requiring an answer”.  If there is no issue between the parties on a matter, there is nothing to answer;  and if there is an issue between them, but the party bearing the burden of proof  has tendered no evidence of it, the opponent is not required to answer.  Where it is not established that an admission was made by one employee rather than another, there is nothing to explain or contradict in relation to the first employee.

   [17] J D Heydon Cross on Evidence (LexisNexis Butterworths, 12^th ed, 2020) at [1215]. Footnotes omitted.

   The Witnesses Generally

2. The events the subject of this dispute are dated, occurring between five and seven years before the witnesses gave evidence.  The Aldi Project concrete works were carried out first between about December 2015 and May 2016. The Lifecare Project works were carried out between about December 2016 and  mid-2017. 

3. Witnesses understandably had difficulties recalling matters and were generally frank about their lack of recall and uncertainty over some. Their answers were often qualified with ‘I don’t recall’, ‘I think so’, ‘perhaps, ‘maybe’ and ‘I can’t recall, no’.  Too often, when a contradictory version of events was put to a witness, the witness qualified their earlier evidence and expressed uncertainty over their precise recollections.

4. Generally, no serious criticism of poor recollections as to the order of events or matters of detail should be made and the relevant documentary evidence is to be preferred for dates and detail in preference to inexact and faded recollections. 

5. There were some matters of importance where the evidence of the various witnesses was unsatisfactory in some respects and warranted specific comment.  For convenience, those comments are made in the context of the relevant topic having regard to the issues in contention.

   The Witnesses Called

   Mr Apostolakos

6. Contek’s only witness was its founder and principal, Mr Paul Apostolakos. Mr Apostolakos was the only witness in the case who gave lengthy evidence.  He was extensively cross-examined, and his credit challenged by Mossop on a number of issues.  Mossop submits his evidence should not be accepted on any topic where it is contentious.

7. Overall, Mossop’s criticisms are overstated.  Whilst it may be accepted there were occasions Mr Apostolakos was prone to exaggerate (such as the water ‘cascading’ into the basement), that does not undermine all of his evidence.  Further, Mossop’s submissions to the effect that it was Mr Apostolakos’ position that ‘everyone else is to blame’ are beside the point and at most reflect his frustration about the dispute over Contek’s variation claims that were stone-walled and then met with a series of back charges and lengthy litigation. 

8. The same criticisms made of Contek’s lack of paperwork could also be made of Mossop’s project management team.  Any such criticism should be disregarded.  It must be acknowledged that whilst both parties were commercial contractors, both are builders, not lawyers, and were plainly focussed on the works required to be done and maintaining a working relationship. As the documentary evidence shows, emails were short, direct and sent infrequently.  There was much informality about on-site communications, as is often the case on busy construction sites.

9. As regards the extra concrete variation claims, Contek’s first claim for the ground floor (V2) was made within four weeks of completing the pour.  In the circumstances where the works involved the change in the concrete mix and regular interactions on site, it is not surprising that there were no contemporaneous written complaints preceding the first concrete variation.  The second and third concrete variation claims were made in May 2017 before any extensive correspondence between the parties about these claims and other outstanding variation claims.  Mossop’s criticism about Contek’s lack of written complaint is therefore unpersuasive.

10. Mossop’s criticism about Contek’s take-off documents should also be disregarded.  The criticism is not relevant to any issue. They were not in evidence because Mossop (reasonably) objected to them being tendered when they were produced at trial for the first time, not having been discovered.  What was relevant was the reasonableness of the volume of standard concrete mix allowed as a credit, an essential component in the calculation of Contek’s variation claims for extra concrete.

11. Even so, given the importance of the issues to the parties, Mr Apostolakos’ evidence has been critically reviewed where it is contentious. Observations relevant to the issues to be determined have been made later in these reasons in the context of the relevant topics.

    Mr Stringer

12. Mr Travis Stringer was Mossop’s site manager for the Lifecare Project. His employment began in late January or early February 2017 after the ground floor slab was poured.  His evidence was relevant to two topics: first, the dispute over his alleged on-site oral direction to raise the finished floor levels on the first and second floors and, secondly, directing Contek to persist with the last pour of the basement in bad weather.

13. Mossop described Mr Stringer as plain speaking and credible. Contek described him as a poor and unreliable witness.  Overall, he was not an impressive witness.  Mr Stringer generally lacked recall and was uncertain of many matters that occurred long ago, qualifying much of his evidence as such.  On the topic of the on-site direction to vary the finished floor levels, Contek’s criticism about his evidence should be accepted for the reasons discussed below in the context of this topic.  However, Contek’s criticisms of his lack of recall of the design changes to the basement are overstated and should be disregarded.

    Mr Orlovic

14. Mr Harry Orlovic was Mossop’s Project Manager and the named Subcontract Superintendent for the Lifecare Project.[18]  Despite his central role in the Lifecare Project his evidence and cross-examination were relatively short.  Both parties submit his evidence should be accepted as reliable. 

    [18] Exhibit A1 page 183, Part A – Subcontract Particulars.

15. However, some aspects of Mr Orlovic’s evidence were questionable when viewed objectively in the context of the wider evidence, particularly on the topic of the on-site direction to vary the finished floor levels.  As with Mr Stringer, the reasons for finding some of his evidence unsatisfactory are discussed below in the context of the relevant issues.

    Mr Mossop

16. Mr Neil Mossop is the managing director of Mossop with decades of experience in the construction industry. 

17. Late in the interlocutory stages between the first and second parts of trial, an application was pressed to call Mr Mossop as an expert witness without having complied with the rules as to a written expert’s  report.[19]  The application was opposed by Contek.  Out of fairness, the Court ruled that Mr Mossop would not be permitted to give opinion evidence on matters calling for the special skill and knowledge of an expert witness. He was, of course, permitted to give evidence on matters observed relevant to the issues in dispute.

    [19] Interlocutory Application  (FDN 77) supported by Affidavit of Nicholas John Anderson made 5 August 2022 (FDN 78). 

18. Mr Mossop was not therefore called as a testifying expert witness.  His lay evidence was of limited scope and assistance in determining the relevant issues because of his limited involvement in relevant matters.  Mr Mossop was not on site during any of the concrete pours for either project.  Mr Mossop’s role primarily concerned the commercial decisions made to approve or reject the contentious variation claims made by Contek, despite the contractual obligations of the Subcontract Superintendent to assess variation claims fairly and reasonably.  Mr Mossop authored the narratives and closely supervised the ensuing litigation.

19. To the limited extent Mr Mossop’s evidence is relevant to the issues in dispute, and subject to the Court’s ruling, it is to be accepted as reliable.  As already stated, the narratives are submission, not evidence, and have been treated accordingly. 

    Mr Lalli

20. Mr Lalli is employed by Mossop as a contract administrator.  He joined Mossop in a site administration role on the Lifecare Project in July 2017 after all floor levels were poured, the structure was up and fit-out was in progress. 

21. Mr Lalli was instructed by his manager, Mr Tziortzis, to take measurements of the distance between the top of the slab and the bottom of the set-downs for the bathroom pods on the first and second floors.  He recorded his measurements on slab plans.

22. Mr Lalli should be accepted as a witness of truth and Contek does not submit otherwise.

    Mr McFarlane

23. Mr John McFarlane is a licensed surveyor and principal of Alexander Symonds.  Mr McFarlane’s expertise is not challenged.  Contek’s complaint about his lack of independence given Alexander Symonds’s pre-existing commercial relationship with Mossop is unpersuasive and should be disregarded.

24. Mr McFarlane gave detailed and considered evidence. He was frank about the limitations of the survey evidence and the derived floor and slab thicknesses. 

25. Mr McFarlane’s evidence should be accepted unreservedly.

    Witnesses Not Called

    Mr Kemp

26. Mr Kemp was Contek’s foreman and Mr Apostolakos’ right hand for the Lifecare Project.  He was involved in the on-site discussions about the varying levels of the Deltacore floor panels and the basement pour in bad weather.  Given the way the evidence fell from the other witnesses, it should be accepted that Mr Kemp’s evidence would have elucidated relevant matters. His absence as a witness has been taken into account as not assisting Contek’s case in determining relevant matters where appropriate.

    Mr Barone

27. Mr Joe Barone was as estimator employed by Mossop and named as its contact for the concrete works tenders for the Lifecare Project. Mr Barone had carriage of negotiations with Mr Apostolakos in late September 2016 over a revised subcontract price for a revised scope of works during a formal tender process. 

28. Mr Barone’s evidence was most relevant to Contek’s rectification claim.  In his absence, it should be inferred that Mr Barone’s evidence on the topic would not have added anything to the matters clearly expressed in the relevant email correspondence.

    Mr Zilic

29. Mr Tomi Zilic was a contract administrator employed by Mossop for the early stages of the Lifecare Project.  His involvement was largely documented and only of relevance to Contek’s rectification claim.  It should be also inferred in his absence that Mr Zilic’s evidence on this topic would not have added anything to the matters clearly expressed in the relevant email correspondence.

    Mr Tziortzis

30. Mr Kosti Tziortzis was employed by Mossop during the Lifecare Project.

31. Mr Tziortzis’ absence as a witness calls for comment on one issue.  He was the author of an email sent to Mr Apostolakos on 22 August 2017 attaching site plans recording the measurements taken by Mr Lalli.  In this email he referred to a telephone conversation with Mr Apostolakos on the previous day during the course of which Mossop alleges certain things were agreed, including as to the costs of retaining Alexander Symonds to conduct a survey of the thickness of the topping slabs.

32. In circumstances where the parties were in dispute and in the absence of an opportunity to test his evidence, his email referring to an agreement reached on the telephone should be given no weight.

    PART D: LIFECARE PROJECT – TOPIC 3 - EXTRA CONCRETE

    The Dispute – $58,008.38 ex GST[20]

    [20] $63,809.22 inc GST.

    The Variation Claims

33. Contek made three variation claims (V2, V6 and V8) for additional concrete used in the topping slabs (concrete variation claims).

34. The original subcontract scope of works required 60mm[21] mesh reinforced concrete topping slabs to be laid over precast concrete ‘Deltacore’ panels that were to be installed by another subcontractor under Mossop’s supervision.  Structural design changes were made to the concrete mix and reinforcing to be used in the 60mm topping slab and it is uncontentious these changes were valid variations to the subcontract scope of works and adjustments to the subcontract sum.

    [21] There were some set-downs where the specified topping thickness was 160mm or 400mm.

35. V2[22] concerns the ground floor topping slab that was poured between 20 and 30 January 2017. The claim is dated 25 February 2017 and described as:

    DETAILS: Variation – Steel Fibres to Ground Floor Topping Slab in Lieu of Mesh & Additional Concrete Used Due to Discrepancies in Deltacore Floor[23]

    [22] Exhibit A3.1 page 145.

    [23] Emphasis supplied.

36. V2 claims 241.7 cubic metres @ $301/cubic metre for a Helix fibre concrete mix (Helix mix) less credits for 148 cubic metres @ $162/cubic metre for a standard 32 MPa concrete mix (standard mix), the supply of mesh reinforcement (8.3 tonnes) and labour to fix the mesh reinforcement. It also includes minor claims for additional concrete testing and pumping, a 5% administration fee and GST. 

37. V6[24] concerns the first floor topping slab that was poured on 28 March 2017.  The claim is dated 17 May 2017 and described similarly, referring to additional concrete being used due to discrepancies in the Deltacore flooring.  V6 claims 183.4 cubic metres @ $301/cubic metre for a Helix mix less credits for 111.24 cubic metres @ $162/cubic metre for a standard mix, the supply of mesh reinforcement (6.27 tonnes) and labour to fix the mesh reinforcement.  It also includes minor claims for additional concrete testing and pumping, a 5% administration fee and GST. 

    [24] Exhibit A3.1 page 147.

38. V8[25] concerns the second floor topping slab that was poured on 5 May 2017.  The claims is also dated 17 May 2017 but is described as:

    DETAILS: Variation – Steel Fibres to Second Floor Topping Slab in Lieu of Mesh

    [25] Exhibit A3.1 page 149.

39. V8 claims 143.5 cubic metres @ $301/cubic metre for a Helix mix less credits for 92.22 cubic metres @ $162/cubic metre for a standard mix, the supply of mesh reinforcement (5.6 tonnes) and labour to fix the mesh reinforcement.  It also includes minor claims for additional concrete testing and pumping, a 5% administration fee and GST. 

40. Ultimately, on 30 May 2018, after an interim assessment made in September 2017 and much dispute by correspondence, Mossop issued variation orders[26] approving Contek’s claims for an increased price ($139 more per cubic metre) for the more expensive Helix mix but for only some 20% of the additional volume of concrete claimed and for only the first and second floors. No additional volume was allowed for the ground floor. Mossop calculated the approved volumes on the basis of estimates of the average slab thickness for each floor derived from a survey of the AsBuilt floor thicknesses by licensed surveyor Mr John McFarlane of Alexander Symonds[27] and a measure undertaken by the project quantity surveyors, WT Partnership.[28]

    [26] Exhibit A3.1 pages 260-67. The credits allowed for mesh reinforcement and labour omitted from the subcontract scope of works by reason of the change in concrete mix were also approved.   

    [27] Exhibit A3.1 pages 261, 245 and 252 for the ground, first and second floors respectively.

    [28] See [198]-[205] below.

    Claimed Additional Volumes

41. The parties’ dispute therefore concerns only one component of Contek’s concrete variation claims:  the claimed extra volume of Helix mix.  The following table sets out each variation claim and Contek’s calculation of the additional volumes in cubic metres.

    Table 3

No.	Description	Actual Supplied (m3)	Less Original Allowance (m3)	Additional Claimed (m3)
V2	Extra Concrete – Ground Floor	241.7	148	93.7
V6	Extra Concrete – First Floor	183.4	111.24	72.16
V8	Extra Concrete – Second Floor	143.5	92.22	51.28
Total	568.6	351.46	217.14

1. There is no substantive basis for disputing the actual supplied volume of Helix mix for the topping slabs as proven by the Hanson delivery dockets. Mossop’s counsel properly conceded the issue in the second part of the trial.[29]  The Hanson delivery dockets[30] prove supply of 550.3m³, that is 18.3m³ less than the total claimed by Contek as shown in the first column of Table 3 above.  Contek’s claim should be reduced accordingly. 

   [29] T23.11-.13.

   [30] Exhibit R17 pages 578 to 707. See also Exhibit A14 which overstates the volume of Helix mix supplied by 6.1m³.

2. Mossop submits ‘returns’ and ‘cancelled but charged’ volumes were incorrectly claimed by Contek.[31]  As to ‘returns’, they are charged and properly claimable and should be factored in as waste in any event since unused concrete is not usable on return.[32]  In the absence of any specific evidence about the cancelled and invoiced delivery, it should be also considered as waste and is properly claimable.

   [31] Written Submissions of the Respondent [110].

   [32] Mossop conceded as much in its Written Submissions of the Respondent [126.4].

3. The volumes shown in the second column of Table 3 above are the subject of dispute as to the adequacy of Contek’s original allowance for concrete for the topping slabs as specified in the contract drawings. This is ‘Issue 4’ considered below.[33]

   [33] See [290]-[327] below.

4. Table 4 below sets out for each variation claim the additional volumes claimed, those allowed on assessment and paid with the difference being the volumes in dispute.

   Table 4

No.	Description	Additional Claimed (m3)	Assessed & Paid  (m3)	Disputed (m3)
V2	Extra Concrete – Ground Floor	93.7	0	93.7
V6	Extra Concrete – First Floor	72.16	32.65	39.51
V8	Extra Concrete – Second Floor	51.28	12.7	38.58
Total	217.14	45.35	171.79

1. Table 5 below sets out for each variation claim, the total value claimed, the final approved value and adjustment to the subcontract sum and the disputed value.

   Table 5

No.	Description	Claimed Value ex GST	Approved Value ex GST	Disputed Value ex GST
V2	Extra Concrete – Ground Floor[34]	$36,217.97	$4,977.00	$31,240.96
V6	Extra Concrete – First Floor[35]	$26,973.24	$13,250.59	$13,722.65
V8	Extra Concrete – Second Floor[36]	$18,590.52	$5,545.76	$13,044.77
Total	$81,781.73	$23,773.35	$58,008.38

[34] Exhibit A3.1 page 261.

[35] Exhibit A3.1 page 245.

[36] Exhibit A3.1 page 252.

The Parties’ Contentions

The Pleadings

1. Contek pleads the subcontract works were varied by a change to the concrete mix design and additional concrete was required to be supplied to raise the finished levels of the topping slabs “due to significant voids and inconsistencies in the Deltacore floor”.[37]  No detail is pleaded as to the nature of the “significant voids and inconsistencies” except by inference from allegations pleaded in its reply as to the consequential raising of the floor levels and reference to photographs of the ‘inconsistent’ Deltacore panels sent to Mossop.

   [37] Claim [6.1], [6.3] and [6.5].

2. Mossop admits the subcontract specification was changed to a Helix mix and the reinforcing mesh deleted[38] from the topping slabs but denies there were voids and inconsistencies in the Deltacore floor other than those to be expected and known to Contek.[39] This plea should be understood as referring to such voids and inconsistencies as specified in the original scope of works as shown by the contract drawings.

   [38] Defence [6.1.1.2].

   [39] Defence [6.1.2.1].

1. Mossop’s pleaded denial of any significant voids or inconsistencies in the Deltacore floor other than those known or expected was never sustainable on the evidence as acknowledged by its own assessment that some additional concrete was required. Mossop’s own survey results indicate a significant degree of variability in slab thickness and by implication the evenness of the underlying Deltacore floor, on the reasonable assumption that the finished tops of the slabs were flat. 

2. In opening Mossop’s case, its counsel conceded that the finished floor level was raised for part of the second floor, and by implication that the Deltacore floor in at least that area was excessively cambered.  Unsurprisingly given the course of the evidence, by the close of trial Mossop’s case had shifted to the Deltacore floor not being “proved to be nearly as uneven” as Mr Apostolakos asserted in his evidence.[40] 

   [40] Written Submissions of the Respondent [93].

3. The real dispute about this issue is therefore the extent to which the Deltacore floor panels were uneven and in what other respects there were unexpected ‘inconsistencies’ (if any) requiring additional concrete and an adjustment to the subcontract sum.

4. As to contractual entitlement in answer to the allegations concerning extra concrete, Mossop pleads in the most general of terms that Contek did not comply with “the contract pertaining to notification of variations but… in any event says that instead any extra concrete… has been resolved and paid…”.[41] 

   [41] Defence [6.1.2.2] and [6.1.2.3].

5. No supporting material facts or particulars of the relevant contractual provisions are pleaded.

6. Mossop further alleges that it was agreed that Mossop would pay for the volume of additional concrete used according to the results of the Alexander Symonds survey and the parties would share the costs of the survey.  Mossop denies liability for any further amount by reason that, as allegedly agreed, it has paid Contek for additional concrete on the basis of the calculation of average slab thickness derived from the survey results. 

7. Mossop puts in issue the required and actual volumes used, relying on estimates of the topping slab concrete (including “the gaps between the panels and infills”[42] based on the Deltacore drawings) made by quantity surveyors WT Partnership. Mossop denies any significant change between drawings, alleging a reduction in the concrete actually required.

   [42] Defence [6.1.10].

8. In reply, Contek pleads that by reason of “the inconsistencies” in the Deltacore floor, the concrete levels were raised on site at the direction of Mr Travis Stringer,[43] up to 60mm in some areas[44] and 60mm from the highest point,[45] and denies any agreement binding it to the results of the Alexander Symonds survey.

   [43] Reply [2.2] and [7].

   [44] Reply [3.2].

   [45] Reply [7.2].

9. Contek pleads in the alternative to its contractual claim for damages, a restitutionary claim for quantum meruit. This claim was not addressed by either party at trial, save a passing reference made in closing by Contek’s counsel to the relevant pleading.  It is neither necessary nor appropriate to consider this claim in circumstances where Contek has enforceable contractual rights to recover damages or moneys due under the subcontract that are inconsistent with a restitutionary remedy.[46]

   [46] Mann v Paterson Constructions Pty Ltd (2019) 267 CLR 560.

   The Parties’ Contentions at Trial

10. The focus of Contek’s case at trial was the appropriate measure for the volume of additional concrete used to value Contek’s concrete variation claims.  Subsidiary but important factual disputes concerned the verbal on-site direction allegedly given by Mossop’s Site Manager, Mr Stringer, to raise the finished floor levels and the extent of the inconsistencies in the Deltacore floor panels and requirement for additional concrete as alleged or otherwise. 

11. Contek’s pleaded case gave no regard to the subcontract terms entitling an adjustment to the subcontract price by reason of a variation to the scope of works for the additional volume of concrete claimed.  Contek submits the dispute the Court is required to determine is confined to the extent to which Contek should be paid for the increased volume of concrete mix based on the volume actually supplied less its tender allowance based on the original scope of topping slab concrete works as shown in the tender drawings.

12. To illustrate the conceptual problem to be resolved by the Court, Contek used the analogy of pouring water into a bucket filled with stones to describe pouring the topping slabs on top of the inconsistent Deltacore floor. It submits the best way to measure the additional amount of concrete (or water) poured into the topping slabs (or bucket) is to measure the actual amount poured and deduct the tender allowance.

13. This was referred to by the parties variously as the ‘bucket theory’ or ‘bucket method’ of measuring the extra concrete claimed.

14. Mossop submits the ‘bucket theory’ advanced by Contek is flawed and unproven because it disagrees that the issues to be determined are confined to just the actual volume of concrete delivered to site and, consistent with Mossop’s pleaded defence, challenges Contek’s claimed entitlement to an adjustment of the subcontract sum for additional concrete on a number of broader bases, generally criticising Contek’s case as implausible, illogical and unproven. 

15. The grounds of defence presented at trial by Mossop were numerous. First, (despite the formal approval of some of Contek’s claim for an additional volume of concrete and adjustment of the subcontract sum) it contends there was no direction or instruction from Mossop for additional concrete topping as pleaded by Contek or otherwise.  Secondly, the claims are contract barred because Contek did not comply with its obligations under clause 24.2 of the subcontract to give a notice of variation. [47] Thirdly, Contek has not proved that an additional 60mm of concrete was added to the topping slabs in circumstances where Mossop has reliably proved the average slab thickness was less than claimed. Fourthly, there are other explanations as to where the additional concrete went that are as expected (including that Contek underestimated the volume of concrete required) and therefore not to Mossop’s account. Fifthly, Mossop has paid for the additional concrete as agreed would be quantified by the Alexander Symonds survey. Sixthly, there is no claim for ‘voids’. 

    [47] Written Submissions of the Respondent [48]-[52].

    The Issues to be Determined

    The Ultimate Question

16. Properly framed, the ultimate question to be determined by the Court is how much of the disputed claimed additional concrete is extra to the subcontract scope of works and constitutes a variation entitling Contek to a further adjustment to the subcontract sum.  Contek’s claim is therefore not confined to slab thickness as Mossop contends.  Nor is the question simply one of the preferred valuation method as Contek submits, that is, determination of the method that most reliably quantifies the additional volume of concrete supplied.

17. It is not necessary to address the ‘bucket theory’ further. 

    Not Just Slab Thickness

18. Mossop’s first contention is that gaps between the Deltacore panels (joints) and voids (infills) in them are not the subject of Contek’s concrete variation claims.[48] That is not correct.  Discrepancies in the nature of gaps and voids are plainly the subject of these variation claims, just as are the varying levels of the underlying Deltacore floor. These claims were generally described as being “due to discrepancies in the Deltacore floor” and extra concrete required for gaps and voids is necessarily included by calculating the claim by reference to the volume of Helix mix delivered to site by Contek’s supplier, Hanson. The concrete delivered to site was used to pour the topping slabs over Deltacore floor panels of varying heights laid with gaps between the panels (joints) and voids (infills) and fillings to cored Deltacore panels as specified in the drawings.

    [48] T124.33-.36; T125.4-.7.

19. Plainly, the Court is only required to determine an issue to the extent it is raised on the pleadings and the parties are, as a general rule, confined to the pleaded causes of action and defences agitated at trial.  Where an unpleaded claim is agitated at trial and a party has adequate notice of the case it has to meet generally, it will not generally matter that findings are made and judgment is given on unpleaded claims.[49]

    [49] NRM Corporation Pty Ltd v ACCC [2016] FCAFC 98 at [26].

20. Contek pleads that additional concrete was required to raise the finished floor level due to significant ‘voids’ and ‘inconsistencies’ in the Deltacore floor.[50]  As already emphasised, the nature of such ‘voids’ and ‘inconsistencies’ was not detailed or explained further in Contek’s pleadings, save for reference in its reply to photographs showing the ‘inconsistent’ Deltacore panels[51] and references to an on-site instruction to raise floor levels (i.e. slab thickness).[52] 

    [50] Defence [6.1.2]; Reply [2], [3] and [7].

    [51] Reply [2.1].

    [52] Reply [2.2], [3.2], [7.1] and [7.2].

21. Mossop did not complain about the generality of Contek’s pleaded case before trial.  Before proceedings were instituted, Contek’s claims were the subject of a protracted assessment process under the subcontract and extensive correspondence.  It should therefore be inferred that the parties well knew the issues in dispute.  Mossop’s first objection about a claim for ‘gaps’ was late and made part-way through the second part of the trial despite Contek’s counsel having opened Contek’s concrete variation case twice (10 months apart) on there being extensive ‘gaps’ and ‘voids’ in between Deltacore floor panels of varying heights and after evidence had been received on this topic in both parts of the trial.[53]  Whilst Mossop concedes this evidence is relevant contextually, it contends Contek has confined its concrete claims to the pleaded ‘voids’ and ‘inconsistencies’ that raise the finished floor level so that the only claim it must meet concerns only slab thickness.  That is, there is no pleaded case of ‘gaps’ between panels (joints) or ‘voids’ that Mossop must meet.[54] 

    [53] T125-157.

    [54] T143.24-.29.

22. Yet Mossop joined issue in its pleaded defence as to whether there were significant ‘voids’ and ‘inconsistencies’ in the Deltacore floor.  It did so by first denying there were any other than those expected and known to Contek[55] and secondly by alleging that “gaps between the panels and infills based on the Deltacore drawings” were required to have been included in Contek’s tender allowance.[56] Accordingly, Mossop put in issue the contribution of all ‘voids’ and ‘inconsistencies’ in the Deltacore floor to the usage of additional concrete by alleging there were not any that were compensable.

    [55] Defence [6.1.2].

    [56] Defence [6.1.10].

23. Any suggestion that Mossop did not know it had to meet the case Contek presented at trial and was caught by surprise is uncompelling and should be rejected.  During the works, Contek complained at an early stage about the extent of ‘voids’ and ‘gaps’ in the Deltacore floor on the ground floor and then again, when preparing to pour the first floor, Mr Orlovic, Mossop’s Project Manager and Subcontract Superintendent, instructed that they were “unavoidable” and needed to be blocked up.[57]  From the outset, Contek claimed additional concrete by reference to all the concrete supplied less its tender allowance, thereby claiming the volume poured into the topping slabs and into the gaps between the panels (joints) and voids (infills and fillings of cored panels) as the drawings specified.

    [57] Exhibit A3.3 pages 813-14.

24. During the assessment process, Mossop rejected these claims on numerous grounds including where else the concrete might have gone such as the ‘voids’ and ‘gaps’ that were expected and known to Contek.

25. In any event, Mossop has met at trial the claim for ‘gaps’ it objects to as not being pleaded.  It has done so by way of extensive written submissions that expressly address ‘gaps’ between the panels (joints), ‘voids’ (infills and fillings of cored panels) and varying levels in the Deltacore and whether they are compensable as a variation to the subcontract scope of works,[58] without adducing any expert evidence on the topic.

    Not Just a Valuation Question

    [58] Written Submissions of the Respondent [65] to [129].

26. The ultimate question to be determined is also not just a question of valuation as Contek submits.

27. The starting point is Contek’s contractual entitlement to claim a variation and adjustment to the subcontract sum in the circumstances found to the extent contractual entitlement is an issue raised on the pleadings. 

28. This qualification is important because only one issue of contractual non-compliance was pleaded by Mossop as regards Contek’s concrete variation claims.  That is Mossop’s previously mentioned defence of Contek’s alleged non-compliance with contractual notices for variation. The relevant provisions are obvious from reading the subcontract conditions, although none are expressly pleaded.  As Mossop’s counsel put it, “it’s impossible to think that a competent counsel” did not know or understand the relevant subcontract clauses.[59] The same may be said for both parties and should be borne in mind in considering the limited scope of Mossop’s pleaded defence of contractual non-compliance and is not a basis for extending the grounds of defence to include unpleaded contractual defences.

    [59] T799.19-22.

29. The valuation question involves consideration of a number of controversial factual issues of some complexity. First, what was the nature and extent of unexpected and unknown ‘inconsistencies’ in the Deltacore floor?  Secondly, how (if at all) did any such inconsistencies result in a requirement for additional concrete, including whether any on-site directions were given to increase the finished floor levels? 

30. This issue of what was additionally required is multifaceted.  It requires an analysis of why more concrete was used or, as Mossop colloquially described it: ‘where did the concrete go?’  Mossop contends it has not just gone into thicker topping slabs to the extent claimed and relies on measurements taken of the slab thickness in the bathroom set-downs and the Alexander Symonds survey and calculations of average slab thickness to prove its case.

31. The adequacy of Contek’s ‘tender’ allowance is disputed.  If it was inadequate, as Mossop ultimately contends, it follows more concrete should have been used than estimated and is not additional and a variation to the subcontract scope of works.

    The Issues to be Determined

32. The Court has approached resolution of the parties’ dispute over the concrete variation claims by first considering evidence of topics that are foundational to the key issues.

33. The survey evidence is particularly important for two reasons. First, there is the highly contentious question as to what reliance can reasonably be placed on these results to determine the validity of the claimed additional concrete volumes. The second reason is more basic. Despite their limitations, these survey results are the best evidence of significant variability in the thickness of the topping slabs due to variation in the levels of the underlying Deltacore floor panels. The survey results support the other evidence as to vertical ‘discrepancies’ and ‘inconsistencies’ in the Deltacore floor.  Plainly, they shed no light on horizontal ‘discrepancies’ and ‘inconsistencies’ in the Deltacore floor.

34. On this foundation, the following key issues to be determined are considered and answered.

    1.     Was there an instruction or direction constituting a variation?

    2.     Are these variation claims contractually barred?

    3.     Is the Alexander Symonds survey result binding?

    4.      Was Contek’s standard concrete allowance adequate?

    5.     What is a fair and reasonable measure for any additional concrete?

    The Evidence

    The Topping Slab Works

35. To properly appreciate the significance of the technical evidence it is necessary to consider the specified scope of works, the method for pouring the topping slabs and the areas involved. 

36. Contek’s scope of works included installing the formwork for and pouring of topping slabs over Deltacore precast concrete floor panels on the ground, first and second floors of the building being constructed by Mossop.

37. The precast panels come in various lengths, are 1197mm wide and 205mm deep.[60] The panels are formed with core holes (where they are extruded) and are fitted with tensioning reinforcing rods top and bottom that run the length of the panel. The tensioning rods cause the panels to be cambered (curved) along the length of the panel.  The high point of the camber was referred to in the evidence as the ‘hog’. The camber in the panels is expected to settle under load from the concrete topping slab. 

    [60] Deltacore floor panel drawings Exhibit A3.1 pages 140 and 142.

38. The floors on the first and second levels of the building were formed by laying individual Deltacore panels on suspended structural steel frames in two directions and pushing them together. The ground floor was similarly formed by laying Deltacore floor in two directions on structural steel but between two raft slabs (poured separately in a different concrete mix).

39. Concrete was then poured on top of the Deltacore floor panels to form the concrete topping slab[61] that covers the Deltacore panels and fills the gaps between the panels (joints) and any specified voids (infills) in the panels or between the panels and structural steel or precast walls and fills specified cored sections of panels (fillings) where reinforcing bars were to be screwed in.

    [61] Deltacore marking plans Exhibit A3.1 pages 139, 141 and 143.

40. On the first and second floors two edge beams (one 400mm thick the other 175mm thick) surrounded the topping slabs and were poured with a different mix of concrete.

41. The Deltacore marking plans[62] specified the layout of the panels and the joints and infills to be filled with topping slab concrete.  The structural slab plans showed the areas where the Deltacore floor panels were to be laid within the 400mm and 175mm edge beams.  The Deltacore floor was not to be laid where there were voids for lifts and stairwells or in the set-downs for prefabricated bathroom pods in the bedrooms on each floor.

    [62] Exhibit A3.1 pages 139, 141 and 143.

42. The Deltacore panels were rebated and chamfered at the top so the joint between adjacent panels was wider at the top than at the bottom.  The standard width of the rebate at the bottom of the chamfer is 21.5mm.  The chamfer on each is 15mm. Gaps between the bottom of the panels were specified on the marking plans to be 3mm. Therefore, the expected width of the joint between panels laid 3mm apart at the bottom of the chamfer was 46mm and at the top of the chamfer, 76mm.[63]

    [63] That is 21.5mm x 2 + 3mm + 15mm x 2.  See Deltacore floor panel drawings referred to above.

43. Connections and other details (such as where the break outs of the top of panels were to be cored for balcony reinforcing to be screwed in and then filled with topping slab concrete)[64] were shown on the structural drawings.

    [64] For example, drawing S23:00 Sections 21 and W. Exhibit A3.1 page 15b.

44. The boards used to form the topping slabs were 95mm high. This benchmark was referred to in the evidence to assist in appreciating heights and widths in photographs of the works during construction.

45. The standard mix was to be reinforced with SL72 fabric (reinforcing mesh) throughout. In January 2017, the standard mix was changed to a Helix mix and the reinforcing mesh was omitted.

46. The usual method for pouring and setting the finished level of the topping slabs was uncontentious. Before pouring the concrete, Contek was required to undertake various preparatory works such as installing formwork for the different pours, the bathroom set-downs (pods) and edges (such as on top of precast walls and around lift and stairwells). It was also required to core or break out sections of the Deltacore panels and screw in reinforcing bars as well as blocking up areas to stop concrete bleeding through cracks and gaps.

1. Mossop contracted a surveyor to set the finished floor level for each topping slab by marking a post with a datum as Contek’s reference point in setting the finished levels of the concrete it was to supply, pump and place.  Before pouring Contek would ‘check the levels’ by putting a laser level across the floor. Mr Apostolakos explained in evidence this involved him and his site supervisor, Mr Kemp, walking around the floor using a staff and tripod with a laser light to check that the datum set by Mossop’s surveyor met the required cover, that is, a slab thickness of 60mm.  It was during this process that Mr Apostolakos and Mr Kemp identified significant variation in the height of the Deltacore floor panels affecting the amount of cover that could be achieved by a 60mm topping slab in many places.

2. Based on Contek’s ‘Bluebeam’ take-offs, the areas of the topping slabs and corresponding volumes for a 60mm thick slab (not allowing for wastage, joints, gaps or voids,  the bathroom set-downs or 160mm thick slabs) were as follows.[65]

   Table 6

   [65] Calculated by Mr Apostolakos using Bluebeam software.  Exhibit A3.1 pages 158-60 and pages 173-75 in colour.

Floor	Ground	First	Second	Total
Area (m2)	2,525.73	1,869.59	1,552.46	5,947.78
Less Voids (m2)	61.47	15.56	15.54	92.57
Net Area (m2)	2,464.26	1,854.03	1,536.92	5,855.21
Net Volume (m3)	147.86	111.24	92.22	351.32

1. These were the net areas and volumes used in Contek’s concrete variation claims for additional concrete required by reason of unspecified ‘discrepancies’ in the Deltacore floor panels.  The volumes are simply calculated as the area x 60mm.

2. Whilst the required volumes are challenged, the areas ultimately were not, and the same or nearly same areas (depending on the floor) were used by Mossop in its final assessment.[66]

   [66] The same area was used for ground floor, and the differences for the first and second floors was immaterial. See Exhibit A3.1 pages 261, 245 and 252 for the ground, first and second floors respectively; T196.18-.21.

   Mossop’s Assessment

3. The documentary evidence of Mossop’s initial assessment of the concrete variation claims is the best contemporaneous evidence of the real issues in dispute.  This evidence gives important context to the witnesses’ oral evidence about events that by the time of trial were distant, accepting that it was difficult for all of the witnesses to reliably recall what had happened so long ago.

4. Contek submitted variation claim V2 with its 25 February 2017 payment claim within a month of completing the pour of the ground floor. Mossop’s Contract Administrator, Mr  Zilic, reviewed the claim. On 22 March 2017, Mr  Zilic sent Mr Apostolakos an email (copied to Mr Orlovic and Mr Stringer) querying the prices in V2. He asked Mr Apostolakos how he “got to the /cube rates” and for a full breakdown of costs.[67]

   [67] Exhibit A3.1 page 282.

5. Later the same day, Mr Zilic sent Mr Apostolakos a second email (also copied to Mr Orlovic and Mr Stringer) further commenting on V2. He said Mossop expected a net credit and not increased cost from the change in the design of the standard mix to a simpler, less labour-intensive and cheaper solution. His email focussed again on price not quantity. The credit for the standard mix was said to be “light on” because Contek had charged a higher price for a previous variation claim.[68]  No complaint was made about the additional volumes claimed.

   [68] Exhibit A3.1 page 281.

6. During May and June 2017, Mr Apostolakos asked Mr Zilic multiple times for a response to his email in relation to V2,[69] without any substantive response.  Meanwhile, Contek submitted claims V6 and V8 on about 17 May 2017.

   [69] Exhibit A3.1 pages 275-80.

7. On 14 July 2017 Mr Apostolakos sent by email ‘revised’ variations claims V2, V6 and V8 to Mossop for assessment, together with calculations to substantiate the volume of concrete allowed in Contek’s tender and photographs of the inconsistencies in the Deltacore flooring.[70] The claims were not revised, rather this time accompanied by substantiating material. Contek’s claims led to an immediate exchange of emails between the Mossop representatives and Mr Apostolakos.

   [70] Exhibit A3.1 pages 151-166, 285.

8. Mr Orlovic responded first, stating that he would let Mr Zilic deal with the claim, however:[71]

   …(steel fibre) concrete supplied should match the credit concrete. i.e. 148 cubic metres on ground floor credited against 148 steel fibre concrete. Why do you have it at 241.7m2? which is 93m2 more? It wasn’t used for the perimeter in-situ sections.

   All other perimeter concrete was normal concrete and always allowed for.

   No additional testing will be paid.

   No additional pumping will be paid.

   This brings it down to $4,340 plus admin. For ground floor.

   [71] Exhibit A3.1 page 287.

9. It is telling that Mr Orlovic only complained about the increased volumes for the ground floor. His lack of complaint about the first and second floors is explained in an email sent later that day.

10. Mr Apostolakos replied immediately by email[72] confirming that the only areas used in Contek’s take-off were the topping slabs and that so much more concrete was used than allowed as per the plan because the finished concrete levels on site were raised to accommodate the inconsistencies in the flooring.  He said:[73]

    Harry the levels were raised to such an extent that we had to provide a 30mm rebate to levels 1 & 2 to the slab perimeter for the windows to work in height because they were already made (Travis gave me this instruction on the day of the pour).

    [72] Exhibit A3.1 page 287.

    [73] Exhibit A3.1 page 286.

11. Mr Apostolakos then asked why if additional concrete was used due to the levels being raised, the additional pumping and concrete testing would not be paid. He suggested they may need to meet to review the information.

12. Mr Orlovic responded, agreeing they may need to meet, saying:[74]

    The only floor raised was level 1, by 20mm or so. You can check the RL’s, but RL’s are as per plan except level 1. Also due to the camber in the deltacore the thickness is less than 60mm in the middle section of delta, whereas on the ends it may be more so it evens out.

    You  cannot claim an extra 90m3 over that area.

    [74] Exhibit A3.1 pages 286-87.

13. Some important observations should be made about this email.  First, it explains why Mr Orlovic’s complaint focussed on the volumes for the ground floor when it is appreciated that Mr Orlovic was referring to the raising of the height of the finished floor level relative to the datum point fixed by Mossop’s surveyor.  Secondly, Mr  Orlovic’s last statement was only correct if the engineer’s specification for slab thickness was not met. The specified cover was a minimum 60mm, so any camber in the middle of a Deltacore floor panel required additional depth of cover at the lower ends.

14. Mr Apostolakos replied,[75] stating the levels were raised to the extent that Contek had to provide a 30mm rebate to levels 1 and 2 slabs for the ready-made windows to fit.  For the second time he referred to Mr Stringer, saying he had been given this instruction by him on site on the day of the pour. The difference between the volume of concrete credited and the volume used was the result of raising the finished floor level and “the inconsistency in the flooring”.

    [75] Exhibit A3.1 page 286.

15. Later emails refer to a meeting then being held between Mr Apostolakos and Mr Zilic. According to Mr Apostolakos, it was left for Mr Zilic to go away and check his area take-offs and get back to Contek with a final cost for each floor.  The Hanson delivery dockets were sent to Mossop to confirm the delivered volume.

16. The dispute over these and other outstanding variation claims escalated a month later on 9 August 2017 when Mr Apostolakos sought confirmation of payment of Contek’s outstanding variation claims and threatened to suspend all work on site.[76]  The following email exchange shows that Mr Orlovic did not dispute Contek’s entitlement to be paid for additional concrete per se. He disputed the extent of the claim and required further substantiation by way of a survey to prove slab thickness.

    [76] Exhibit A3.1 page 289-90.

17. Mr Orlovic promptly responded to Mr Apostolakos’ email by emotively saying among other things that Mossop was waiting on Contek to provide the delivery dockets for each truck, describing Contek’s claim as “way over the top”:[77]

    We also believe that you need to prove to us that you used this amount of concrete on the project and where you used it… We have our doubts that your supplier supplied the amounts they claim too, because where did it go?

    [77] Exhibit A3.1 page 289.

18. Mr Orlovic proposed Contek conduct a survey of the floor thickness to prove its claims.  He reported that he and Mr Stringer had measured set-downs and averaged 65-75mm depths, with only a few 80-85mm.  Yet he made no denial of the floor levels being raised due to inconsistencies in the Deltacore floor or despite the third mention of an on-site direction from Mr Stringer to raise the levels requiring additional concrete.

19. Mr Apostolakos replied, reporting on his earlier meeting with Mr Zilic and restating:[78]

    The fact is the floor levels were raised from the original levels due to the inconstancy in the flooring system – this was instructed on site by the site supervisor…

    [78] Exhibit A3.1 page 291.

20. Mr Orlovic replied again:[79]

    We cannot just simply hand over circa $90K claimed without substantial evidence that raising the RL has increased concrete amounts by the amount you are claiming.

    The amounts claimed works out to about 100mm topping slabs throughout the whole slab area – an extra 40mm raised for the entire topping slab areas.

    On site [w]e don’t have 100mm topping slabs.

    The only way is to prove it to us by the survey as suggested. Please have this done and it will get the issue resolved quicker.

    Please include the guys above in any further correspondence as they are looking at this now, not me.

    I have only suggested ways to help you prove the actual thicknesses on site. We are not denying the RL’s were raised for levels 1 and 2.

    Also, please finish the works on site as soon as possible. It is getting to the critical stage now. Ramp drain base and ramp slabs, plus defects rectification.

    [79] Exhibit A3.1 page 291.  Emphasis supplied.

21. Mr Orlovic’s focus on the topping slab thickness ignores the volume of concrete required for unexpected gaps (joints) and voids (infills) due to inconsistencies in the Deltacore floor.

22. A further exchange of emails occurred. Mr Apostolakos challenged the accuracy of a survey:[80]

    …A survey will do nothing more than provide an approximate average, the dockets provide the EXACT cubic metres pumped and placed.
    We have stated our position clearly, that we believe the cause for the additional concrete placed was the inconsistency in the floor, and this was shown when the floor was checked for the level and there was as little as 0-10mm cover in places…

    
    

    [80] Exhibit A3.1 page 294.

23. Mr Orlovic had the last word:[81]

    Exactly! You are only entitled to be paid for anything additional to the 60mm topping and as advised for the ground floor there are 160mm sections that you should have allowed for, so in these areas anything over 160mm.

    The survey is the only way to prove the extra topping that was poured and that you are entitled to be paid for.

    [81] Exhibit A3.1 pages 294.

24. Mossop responded to the threat to suspend with a formal contract notice requesting recommencement of the works.[82]

    [82] Exhibit A3.3 page 846.

25. In the 14 July and 9 August email exchanges Mr Orlovic made important concessions whilst the project was ongoing and when it should be expected that he was well aware of what had occurred on site and his memory had not been dulled or lost by the passage of many years.  His oral evidence is to be viewed in this context.

26. Mossop’s submission that the importance of these concessions are overstated and should be seen as conciliatory should not be accepted.[83] Mr Orlovic’s tone was not conciliatory.  He was the Subcontract Superintendent. No dispute was raised about the alleged on-site direction to raise the levels for the first and second floors that was referred to three times.  It was also accepted that the slabs for these floors were thicker than the specified 60mm because the levels were raised on these floors. Rather, the increased thickness of the ground floor was disputed. The key issues were the extent to which the raised levels required the volume of additional concrete claimed and how best the volume of additional concrete should be measured. 

    [83] Written Submissions of the Respondent [47].

    Set-Down Measurements

27. Mossop employee Mr Lalli was then instructed to measure the topping slab thickness at the corners of each of the 32 bathroom set-downs on the first and second floors where there was no topping slab covering the Deltacore floor.  Mr Lalli did not measure the ground floor set-downs because the prefabricated bathroom pods had by then already been installed.  His results were recorded by hand on slab plans for each floor.[84]

    [84] Exhibit A3.1 pages 182 and 183.

28. His results are important evidence indicating a thicker than specified topping slab on the first and second floors and only contentious as a measure of reliable additional thickness.

29. In evidence Mr Lalli described how he took these measurements.[85]  He took a tape measure and got down on all fours, at eye-level, and at corners of the set-downs measured the distance from the top to the bottom of the slab that sat on top of the Deltacore floor.  He hand-wrote his measurements on slab plans for each floor as he went.  He took four or five measurements for each of the 64 set-downs.

    [85] T620.1-622.33.

30. Licensed surveyor Mr McFarlane suggested that to measure the slab thickness more accurately, a straight edge should have been used[86]  because it is difficult to read a tape measure, particularly with your head on the floor, and do it hundreds of times consistently.[87] Further, the set-downs were not finished off nicely[88] and accordingly the results were “a bit rough”[89] and indicative rather than precise measurements.[90] These criticisms should be accepted.  Not enough measurements were taken, and they are localised to the set-downs that comprise only a small part of two of the three floors and are not representative of the entirety of the topping slabs.[91]

    [86] T540.5-.6.

    [87] T560.15-31.

    [88] T541.1-.2.

    [89] T551.21-.22.

    [90] T552.11-.12.

    [91] Using Mossop’s figures for the ground floor, the set-downs only occupied 188.76m²  of a total area of 2462.26m². See Table 5 of the Respondent’s Written Submissions at page 36.

31. Whilst it should be emphasised Mr Lalli’s measurements are indicative only and not a basis for reliably calculating the average thickness of the topping slab or the volume of concrete used for the topping slabs, some useful inferences can be drawn from them, nonetheless.

32. Even allowing for a degree of error and imprecision in taking measurements that are self-evidently rounded,[92] Mr Lalli’s measurements show material variability in the depth of the topping slab across both the first and second floors and, by implication, material variability in the height of the Deltacore floor panels underneath, on the assumption the topping slabs were flat on top. 

    [92] All measurements are in 5mm or 10mm integers.

33. Despite their imprecision, these measurements also indicate the topping slabs for the first and second floors were thicker than 60mm and in the majority of the measured parts, some 20 to 30mm thicker, bearing in mind the lower measurements indicate high points in the Deltacore floor panels and the higher measurements, low points.

34. For example, at the set-downs between gridlines E-C and 8-13 on the first floor the measurements range between 70mm and 90mm whereas those between gridlines H-G and 1-7 vary between 60mm and 80mm, with only one (45mm) measurement out of 37 under 60mm. At the set-downs for the last two rooms between gridlines F-D and 1-2, the measurements range between 80mm and 90mm with no measurements below 60mm whilst those for the next four rooms range between 50mm and 75mm, with only one (50mm) measurement below 60mm.  Across a single set-down with a diagonal of some several metres, there are material variations.

35. Generally, the measurements for the first floor indicate additional concrete of up to 30mm thick in places, save for two measured places where the measurements recorded were 45mm and 50mm (indicating high points in the Deltacore floor) and minimum cover would not be achieved from the datum for the finished floor level set by the Mossop surveyor.

36. The measurements for the second floor also indicate additional concrete of up to a 30mm thickness, although the number of higher measurements in the range of 80 to 90mm is noticeably less than for the first floor.  This is consistent with the other evidence showing that less additional concrete was used for the second floor slab than the first floor (e.g. the volume claimed for the first floor is 40% more than for the second floor).[93]  

    [93] That is, 51.28m³ for the first floor and 72.16m³ for the second.

37. Most of the results exceed 60mm and indicate that more concrete than specified was used across the whole of each floor to ensure adequate cover for high parts of the Deltacore floor.  Whilst the increase in the level of the finished slab appears to be material (since 20 to 30mm is one-third to half of the specified slab thickness) these measurements do not assist in reliably quantifying the volume of additional concrete required because the true extent of variability in the entirety of the topping slab is unknown. 

38. Mr Lalli’s measurements support Mr Stringer’s recollection[94] that around an additional 30 to 40mm of concrete was required to lift the topping slab to cover the top of excessively cambered Deltacore panels in the back left-hand area of the second floor, even bearing in mind Mr Lalli’s measurements are necessarily imprecise, and Mr Stringer was uncertain of his recollection from May 2017 as to the precise increase in the finished floor height.[95]  

    [94] See [250]-[252] below.

    [95] T568-33-T569.1

39. That said, Mr Lalli’s measurements do not support the ‘diminishing’ or ‘feathering down’ Mr Stringer described to work the higher concrete down to the design level.[96] 

    [96] T569.17-.32.

    The Alexander Symonds Survey

    Purpose

40. Mr Lalli’s results were provided to Mr Apostolakos by email on 22 August 2017.  He was told at the time that Mossop “still do not know where the extra concrete has gone” because the results did not support Contek’s variation claim to the extent Contek “would have hoped”.[97]  Mr Apostolakos was also told in this email that Mr Orlovic had instructed a surveyor to survey the floors and work out an average thickness of the topping slabs.

    [97] Exhibit A3.1 page 184.

41. As already stated, the average floor thicknesses derived by Alexander Symonds were used in Mossop’s final assessment to calculate the volume of additional concrete it allowed and paid for Contek’s concrete variation claims.

    Instructions and Methodology

42. Mr McFarlane was instructed by Mr Orlovic to undertake a survey of the bottom of the Deltacore floor and top of the topping slab for the purpose of working out an average topping slab thickness.  The survey results were plotted as a series of numbers and crosses on a series of slab floor plans and ultimately the Deltacore panel markings were overlaid to create a second revision of the survey results.  The numbers recorded denote the floor thickness at the surveyed location marked by the adjacent cross.

43. As stated in the survey plan notes, floor thicknesses were calculated at surveyed locations as the difference between AsBuilt floor and ceiling RLs.  The range of results indicates that the Deltacore floor panels were of varying levels, on the reasonable assumption the topping slabs were flat on top.

1. Contek’s assertion that the application of a sealer was always contemplated works outside of Contek’s scope of works, and the issues with the defective concrete surface were conveniently used by Mossop as a back charge for a betterment, should be rejected.[385]  Only the defective sections of the basement were ground, hardened and sealed,[386] as Arrunga’s invoice clearly shows.[387]

   [385] Written Submissions of the Applicant [194]-[196].

   [386] T744.24-.30.

   [387] Exhibit A7 page 176.

2. There is no evidence as to the extra cost involved for just applying the surface hardener. The $12,000.00 ex GST pricing quoted by Arrunga was for grinding 400m² of textured concrete and the supply and application of one coat of hardener and two coats of sealer. Taking a broad brush approach and bearing in mind Arrunga’s quoted price for the grind works carried out by High Gloss Solid Plastering, the betterment should be quantified at $2,000.00 ex GST, being one third of half of the remediation costs.

   Conclusion

3. For the reasons set out above, Mossop has succeeded on it counterclaims for the basement concrete remediation works B11 and B13 in the amounts of $4,359.50 ex GST[388] and $10,000.00 ex GST[389] respectively.

   [388] $4,795.45 inc GST.

   [389] $11,000.00 inc GST.     

   PART G: ALDI PROJECT – TOPIC 10 – CAST IN ANGLES

   Disputed Value - $5,760.00 ex GST[390]

   [390] $6,336.00 inc GST.

4. Contek was contracted to supply materials and labour for the concrete slabs and footings for the main building, the in-situ retaining wall footings and walls and the external concrete pavement for the Aldi supermarket in Berri.

5. The parties agree their dispute over this variation claim is confined to the question of what is a fair and reasonable value for Contek’s variation claim.

6. Contek submitted a variation claim dated 10 March 2016[391] for the additional labour for its works following the redesign of the concrete jointing system in the back-of-house and loading dock areas.  Seven cast-in dowelled constructions joints were required in lieu of saw cut joints.  The total amount claimed was $14,890.00  ex GST.[392]

   [391] Exhibit A10 page 43.

   [392] $16,379.00 inc GST.

7. Mossop assessed Contek’s variation claim[393] by disallowing $5,200.00 ex GST[394] claimed for an additional day of pouring for a concrete crew’s labour plus a pump and deducting $3,264.80 ex GST[395] for costs of installing the saw cut joints.[396]  Mossop paid $6,425.20 ex GST[397] leaving $8,464.60 ex GST[398] in dispute.  At trial, Mossop conceded $2,704.80 ex GST[399] of its calculation of the costs it deducted for installing the saw joints as excessive, leaving only $560 ex GST[400] of that component in dispute.

   [393] Exhibit A10 page 53.

   [394] $5,720.00 inc GST.

   [395] $3,591.28 inc GST.

   [396] Exhibit A10 page 53.

   [397] $7,067.72 inc GST.

   [398] $9,311.28 inc GST.

   [399] $2,975.28 inc GST.

   [400] $616.00 inc GST.

8. The Court is therefore required to determine the remaining dispute over $5,760.00 ex GST.[401]

   [401] $6,336.00 inc GST.

9. It is uncontroversial that the methodology for installing the dowelled construction joints was complicated, time-consuming and involved pouring the concrete slab each side of the joint separately. By comparison, a saw cut joint was made relatively quickly and simply after the concrete slab was poured by chalking the line of the joint and then a worker walking a soft cut machine along the line to cut a 30mm x 3mm joint.

10. Mossop does not dispute Contek’s claim for additional labour to form up and install the cast in angles or Contek’s hourly rates. After hearing Mr Apostolakos’ evidence, Mossop conceded that its deduction for the work involved in making the saw cut joints was excessive, narrowing the dispute to the two components of Mossop’s assessment of Contek’s claim referred to above.

11. The first component concerns Contek’s claim for $5,200.00 ex GST[402] for an extra day to pour the concrete slabs. It was Mr Apostolakos’ evidence that the joint redesign required the resequencing of the planned concrete pours into five pours, each requiring a full concreting crew and pump.  By reference to the original[403] and varied[404] pour sequences marked up on slab plans, Mr Apostolakos explained that the most efficient sequence was to pour the back-of-house and loading dock areas in alternate sections because only one half of the doweled construction joint and corresponding slab could be poured at a time. This changed the size of the pours in those two areas in layman’s terms from one small and one really big pour to two good size pours.[405] This required an extra day for a concrete crew and pump as opposed to two men wheelbarrowing in concrete into the smaller areas at opposite ends of the back-of-house area (denoted in yellow on the slab plan).

    [402] $5,7200.00 inc GST.

    [403] Exhibit A10 page 31.

    [404] Exhibit A10 page 38.

    [405] T301.1-.11.

12. Mossop challenges Contek’s claim as excessive, not making sense and the wheel barrowing not being possible.[406] This submission should be rejected for two reasons. First, there is no evidentiary foundation for Mossop’s analysis of the alleged volumes and work required in contradiction to Mr Apostolakos’ evidence.  Secondly, while Mr Apostolakos was cross-examined on this variation he was not asked any questions challenging the feasibility of the planned pour sequence. 

    [406] Balance of Written Submissions of the Respondent [172].

13. There is therefore no good reason not to accept Mr Apostolakos’ evidence as to why an extra day to pour the concrete slabs was required. Accordingly, Contek’s claim for $5,200.00 ex GST is fair and reasonable.

14. As to the second component of Contek’s claim, a deduction should be made for the labour for the saw cut joints that were not required and omitted from Contek’s scope of works but not to the extent Mossop claims. Accepting that 48m of saw cut joints were no longer required[407] and Mr Apostolakos’ evidence as to the nature of the work involved,[408] one hour’s work valued at $70.00 ex GST[409] would be a fair and reasonable deduction.

    [407] T460.28-.29.

    [408] T309.8; T459.25-.30.

    [409] $77.00 inc GST.

15. It follows that Contek claim for the value in dispute succeeds to the extent of $5,690.00 ex GST[410] and a fair and reasonable value for Contek’s variation claim is as follows.

    [410] $6,259.00 inc GST.

Ex GST	Inc GST
Total Claimed	$14,890.00	$16,379.00
Less costs of saw joint (I hour @ $70)	$70.00	$77.00
Revised Claim	$14,820.00	$16,302.00
Less paid by Mossop	$6,425.20	$7,067.72
Total Outstanding	$8,394.80	$9,234.28

PART H: ALDI PROJECT – TOPIC 11 – ABSENCE FROM SITE

Disputed Back Charge - $9,626.36 ex GST[411]

[411] $10,589.00 inc GST.

1. Mossop claims a set off for a back charge for a variation order[412] referred to by the parties as B1 for the costs of works it instructed other contractors to carry out for works that were indisputably within Contek’s scope of works.  The pleaded basis of the claim is that Contek did not return to site to meet its contractual commitment in line with the construction program.[413]  Contek denies it refused to return to site.[414]

   [412] Exhibit A11 page 17.

   [413] Defence [21.1].

   [414] Reply and Defence to Counterclaim [16.1].

2. At trial, it was uncontentious that Contek was not on site when other contractors undertook the works on Mossop’s instruction. 

3. Contek submits that no requirement to return to site early had been communicated to it before the Christmas closure.  Mossop complains variously that Contek should have been on site to do the relevant works, the relevant works had barely started before the Christmas closure, Mossop and the other contractor were back at work, Mr Apostolakos should have told Mossop he was going away, that he would be uncontactable and when he would be back and had someone in his office to respond to communications in the meantime.[415]  Further, after he had returned to work in January 2016, Mr Apostolakos was grateful Mossop had a replacement contractor do the pour showing he knew it was a proper back charge.[416]

   [415] Written Submissions of the Respondent Topic 11 [6]-[11].

   [416] Ibid [2]-[3].

4. Mossop’s complaints are a distraction and not relevant contractually. The issue is whether Contek was obliged to be on site and complete its works as scheduled.  This depends on the works scheduled in the relevant program and when the Christmas closure occurred.

   The Christmas Closure

5. The Aldi subcontract provides that Contek must carry out its works within the “Site Hours” unless otherwise scheduled.[417] The specified site working hours were Monday to Saturday 7am to 4pm.[418] Both the subcontract and second programs showed a Christmas closure that is referred to in the definition of “Business Day” in the subcontract as the dates scheduled by the Master Builders Association of South Australia Inc.[419]  The dateline in both programs in evidence in hard copy is contracted so that only every alternate day is shown.  It is therefore unclear when the Christmas closure was scheduled to start and finish from the programs in evidence. 

   [417] Exhibit 8 page 13, clause 7 Conditions of Subcontract.

   [418] Appendix E Exhibit A8 page 46.

   [419] Exhibit A8 page 9.

6. However, the dates of the Christmas closure are clearly shown in the “4 Week Program” dated 14 December 2015.[420]  

   [420] Exhibit A11 page 6-7.

7. The dateline in the “4 Week Program” is fully expanded so every day is evident showing the Christmas closure is from Wednesday, 23 December 2015 to Sunday, 3 January 2016 inclusive.  The start of the Christmas closure is confirmed by task 4, “Close up & pour” finishing on Tuesday, 22 December 2023.

8. In the absence of any contradictory evidence, it is reasonable to infer that the expanded subcontract and second programs scheduled the same Christmas closure as the “4 Week Program”.

   The Relevant Program

9. The subcontract program dated 11 September 2015 relevantly provided that Contek’s works (task 50) “Excavate, Rod and Pour Strip Footings” would be undertaken between 10 and 18 December 2015.[421] This task was the preceding critical task before (task 53) “Precast Concrete Erection”, a task that was not within Contek’s scope of works.[422]

   [421] Exhibit A11 page 2.     

   [422] Ibid.

10. The project was behind schedule by mid-December 2015.  The slippage was not of Contek’s making.  The second construction program issued by Mossop and dated 21 December 2015 relevantly provided that Contek’s works (task 47) “Excavate, Rod and Pour Strip Footings” was now scheduled to be undertaken between 14 December 2015 and 15 January 2016 and (task 50) “Precast Concrete Erection” was scheduled for 16 to 21 January 2016.[423]   

    [423] Exhibit A11 page 4.     

11. That was the position on 22 December 2015, the last day of works before the Christmas closure according to the then current subcontract program.

12. On the first day of the Christmas closure, Wednesday 23 December 2015, Mossop’s Project Manager, Mr Talbot, issued Contek with the “4 Week Program” by email sent at 1:49pm to Mr Apostolakos stating that “Contek are required back on site on Friday 8^th January 2016.” [424]  The “4 Week Program” shows as tasks 8 and 9 Contek’s works “Excavate the remaining footings” for 8 January 2016 and “Reo and pour” for Monday 11 to Tuesday 12 January 2016. 

    [424] Exhibit 8 page 6-7.

13. At 2:00pm that same day, Mr Talbot of Mossop sent Mr Apostolakos of Contek a further email, again attaching the “4 Week Program” and noting that Mossop required propping pads prior to 13 January 2016.

14. He did not receive any reply.

15. On Monday, 4 January 2016, Mossop’s Subcontract Superintendent, Mr Main, sent Mr Apostolakos and Mr Kemp (cc to Mr Talbot) an email seeking urgent confirmation that Contek would have plant and labour on site to recommence its works on 6 January 2016.[425]  This was now two days earlier than the “4 Week Program” scheduled date of 8 January 2016 as per the 23 December 2015 emails.

    [425] Exhibit A11 page 8.

16. On Thursday, 14 January 2016, Mossop’s Project Manager Mr Talbot emailed Mr Apostolakos and informed him that he had been unable to get hold of him in the week beginning 4 January 2016, had organised plant and was about to pour the footings in time for the precast erection.[426]

    [426] Exhibit A11 pages 9 and 10.

17. Mr Apostolakos was the only witness who gave evidence on this topic.  His uncontradicted evidence was that he went on holidays before the Christmas closure and was uncontactable until his return on about 14 January 2016.  He did not read the 23 December or 4 January emails until his return.  He was therefore unaware of the “4 Week Program” and Mossop’s requirement for Contek to return to work earlier than previously scheduled on first 8, then 6 January 2016.  Further, if he had known he would have done what was required to meet program.

    Conclusion

18. In the circumstances found, Contek was entitled to rely on the second program that scheduled completion of the relevant footing works on 15 January 2016. Accordingly, Mossop has not shown any basis under the subcontract for removing the relevant works from Contek’s scope of works and setting off the costs of another contractor undertaking the works. Accordingly, Mossop’s set off claim should be dismissed.

    PART I: SETTLEMENT DISPUTE

    Issues in Dispute – Aldi Project Variation Claims B1.0 and B3.1

19. During the course of the trial the parties compromised a number of the claims in dispute. By the end of the trial, the parties were in dispute about the terms of resolution reached as concerns Contek’s variation claims for the cancelled concrete pour (referred to as variation 1.0 or B1.0) and the pylon sign pad footing (referred to as variation 3.1 or B3.1) for the Aldi Project.

20. In essence, Mossop alleges agreement was reached for Contek to forego all its claims for B1.0 ($7,304.00 inc GST) and B3.1 ($6,233.15 inc GST), not just the amounts Contek claimed were in dispute ($2,335.80 inc GST for B1.0 and $958.86 inc GST for B3.1) in successive versions of aide memoires MFI A12 and MFI A19. Contek alleges that the agreement reached did not compromise the amounts it asserted were not disputed by Mossop by reason of admissions in Mossop’s defence, that is, the difference between its claim and the disputed amount.

21. Mossop relies on an affidavit filed by its solicitor, Mr Anderson, exhibiting the relevant settlement correspondence that passed between the parties’ legal representatives and his version of events.[427]  Contek relies on an affidavit filed by its solicitor.[428]

    [427] FDN 99.

    [428] FDN 100.

22. The affidavit material discloses that following discussions between counsel on the evening of the second day of trial, an offer of compromise was put in an email sent by Contek’s counsel to Mossop’s counsel and copied to the instructing solicitors. It was proposed that Contek would forego certain claims in each project in exchange for Mossop foregoing its back charges.  Relevantly, the offer for the Aldi Project was put in the following terms:[429]

    On Aldi Berri, our client will forego all its claims for items B1, B2, B3.1, B3.2, B3.3 and B3.4 totalling $16,006.35 in exchange for your client foregoing its back charges claims for B1, B2 and B3 totalling $16,657.68. Again, the parties respective claims approximately equal/cancel out one another.

    [429] Exhibit NJA-1 to FDN 99.  Emphasis supplied.

23. The offer for the Aldi Project mirrored a similar offer for the Lifecare Project.  The commercial sense of the offer put was clear. Each party would be compromising about the same value so as to limit the issues in the trial given the disproportionate cost of litigating nine claims worth collectively about $33,000.00 that might well cancel one another out.  The item numbers and issues were well understood by the parties given the years of dispute.

24. The totals referred to were readily identifiable as the totals of the allegedly disputed GST inclusive amounts for the Aldi Project claims set out in the spreadsheets prepared by Contek and tendered as aide memoires MFI A12 and MFI A19, that had been the subject of much discussion since Contek’s opening on the first day of trial. For three items, B1.0, B2.0 and B3.1, Contek alleged that Mossop had paid or approved certain amounts ($15,763.15 inc GST), so the amount in dispute in each case was not the full amount of Contek’s claim as presented at trial. 

25. Indeed, Mossop had approved and paid into Court $4,611.75 of Contek’s claim for B3.1[430] and admitted liability in that amount in its defence.[431]  That was not the case for Contek’s claim B1.0, a claim Mossop fully denied and disputed it had ever paid the amount of $4,968.20 inc GST[432] alleged by Contek in its pleading[433] and in aide memoires MFI A12 and MFI A19.

    [430] $4,192.50 ex GST.

    [431] Defence [11.3.1].

    [432] $4,516.55 ex GST.

    [433] Claim and Defence [16].

26. Despite the seemingly obvious, Mossop’s solicitor’s affidavit evidence is to the effect that neither he nor his client Mr Mossop could reconcile to Mossop’s records the total of $16,006.35 for Contek’s claims. However, they were not concerned about an “exact” reconciliation because if the offer was accepted then there would be no further dispute about the items. “Exact” is an odd description, perhaps ‘material’ would be better given the purpose and object of the settlement. 

27. No-one on behalf of Mossop sought to clarify the terms of the offer put by Contek’s counsel. Instead, a counteroffer was put by Mossop that was then rejected and countered by a further offer from Contek to the effect that if Mossop wished to press back charge B1 (absence from site) then Contek would maintain its variation claim B2.0 (cast in angles). Again, the commercial sense was objectively obvious since the amounts in dispute for these claims were of approximately the same value.

28. Ultimately, it was agreed that the identified claims other than variation claim B2.0 (cast in angles) and back charge B1 (absence form site) would be settled.  Contek’s counsel then reported the agreed resolution of the remaining items to the Court.

29. In resolving this final dispute, the first point to be made is that Mossop’s solicitor’s evidence as to his and his client’s subjective intentions about the terms of settlement are not relevant in determining whether a binding agreement had been reached and its terms. What is relevant is what was reasonably conveyed by what the parties’ representatives said and did, bearing in mind the surrounding circumstances as known to the parties, and the purpose and object of the transaction.  

30. The parties’ purpose and object was to reduce the claims to be determined by the Court given the disproportionate cost of continuing to litigate claims of such low value by each foregoing the same approximate value. 

31. It should therefore be accepted that Contek’s offer objectively construed was confined to foregoing the allegedly disputed amounts but not the entirety of its claims. Otherwise, Contek would be foregoing disproportionately more than Mossop when the purpose of the proposed settlement was for each to quit its losses to a similar value.  It makes even less objective sense for Contek to be proposing to forego amounts approved and/or paid by Mossop for which Mossop had admitted liability, even if whether one of those amounts was paid was in dispute.

32. Objectively construed in the circumstances of this case, the parties’ agreement compromised only the disputed amounts of Contek’s variation claims as set out in aide memoires MFI A12 and MFI A19 save for the excluded variation claim B2.0 (cast in angles) in exchange for a compromise of the Mossop’s back charge claims save for excluded back charge B1 (absence from site). 

33. Therefore Mossop’s contention that the parties’ settlement agreement covers the allegedly agreed amounts for variation claims B1.0 and B3.1 of $4,968.20 and $4,611.75 (both inc GST) respectively should be rejected as should Contek’s contention that it should have judgment for both amounts. 

34. Contek should only have judgment in the amount of $4,611.75 inc GST[434] for  variation claim B3.1 for which Mossop has formally admitted liability in its defence.  Contek’s claim for the balance of variation claim B1.0 in the amount of $4,968.20 inc GST[435] fails because it was not admitted or paid by Mossop, was not settled and it would be inappropriate to determine a claim that was not properly agitated at trial and proven.

    PART J:  FORM OF JUDGMENT AND JUDGMENT SUM

    [434] $4,192.50 ex GST.

    [435] $4,516.55 ex GST.

1. As determined, the Lifecare subcontract should be rectified to list revision 00 of the relevant structural drawings S04, S05 and S23 in Appendix D to reflect the common intention of the parties as to the scope of works allowed in the agreed lump sum price negotiated during the formal tender process and the intended basis of contract.

2. Contek should bring into Court a form of judgment reflecting this determination.

3. For neither the Lifecare nor Aldi subcontracts is the resulting judgment sum simply the product of the value of the discrete variation and back charge claims determined by the Court. There are undisputed unpaid invoiced amounts that need to be taken into account. Some are due to Mossop withholding payment of invoiced amounts due on account of its back charge claims and others are for concessions made during the course of the proceeding as to certain other amounts in dispute. To complicate matters further, amounts were paid into Court by Mossop.

4. As stated above, the parties have not reached final agreement on the impact of their differing positions as to the disputed variation and back charge claims on the adjusted subcontract sums net of payments made by Mossop (either to Contek or into Court) under either the Lifecare or Aldi subcontracts.

5. Whilst there is much common ground, the Court will hear the parties on any remaining dispute as to the net amount due under each of the Lifecare and Aldi subcontracts and interest once the parties have had a proper opportunity to consider the Court’s determination of the disputed (Contek) variation and (Mossop) back charge claims as set out in table below.

   Table 12

No.	Description	Disputed Value ex GST	Determined Value ex GST
LifeCare Project
V2	Extra Concrete – Ground Floor	$31,240.96	$26,028.77
V6	Extra Concrete – First Floor	$13,722.65	$6,377.06
V7	Extra Steel – First Floor	$13,503.83	$13,503.83
V8	Extra Concrete – Second Floor	$13,044.77	$8,249.35
V9	Extra Steel – Second Floor	$13,503.83	$13,503.83
B5	Patch & Caulk – Balcony Works	-$10,990.90	-$4,500.00
B10	TC Formwork to Beam Above Ramp	-$3,837.00	Nil
B11	Basement Repairs	-$4,359.50	-$4,359.50
B13	Partial Rectification to Basement Works	-$12,000.00	-$10,000.00
Total	$53,828.64	$48,803.34
Aldi Project
B1.0	Cancelled Concrete Pour	$4,516.55	Nil
B2.0	Extra Cast-in Angles & Slab Redesign	$5,760.00	$5,690.00
B3.1	Pylon Sign Pad Footing	$4,192.50	$4,192.50
B1	Absence from Site	-$9,626.36	Nil
Total	$4,842.69	$9,882.50

PART K:  COSTS

1. The parties should be heard on the question of the costs of the proceeding.