One Set of Expert Evidence for Two Courts: Wallace Estates v Durkan [2026] EWHC 2133 (TCC) and What the Joint TCC–FTT Blueprint Means for Surveyor Expert Witnesses (November 2026)

By 20 November 2026, the experts in one of the most closely watched building safety cases in England must have completed their site inspections at Centrillion Point in Croydon. Ten days later, on 30 November 2026, the fifth edition of the RICS professional standard Surveyors acting as expert witnesses takes effect [5]. Together, those two dates mark a turning point for expert witness evidence building safety claims: the courts now expect a single, CPR Part 35-compliant body of expert opinion to serve both the Technology and Construction Court (TCC) and the First-tier Tribunal (FTT) at the same time.

The decision behind that expectation is Wallace Estates Limited v Durkan Estates Limited & Anor [2026] EWHC 2133 (TCC), handed down on 10 August 2026 by Mr Justice Constable of the TCC and Judge Siobhan McGrath, President of the First-tier Tribunal (Property Chamber), after a joint case management conference on 31 July 2026 [1]. Commentators have described it as the first joint judgment of its kind [3]. This article explains what it decided and what it means for surveyors who act as experts.

This article is general information about a published judgment and is not legal advice.

Key Takeaways

• The TCC and the FTT will manage and hear the Centrillion Point proceedings together, with a single set of expert evidence in architecture, fire engineering and quantity surveying [1].
• CPR Part 35 governs all of that expert evidence; FTT Rule 19 applies only where it is consistent with Part 35 [1].
• Experts of like discipline must hold CPR 35.12 discussions and file joint statements, with reports limited to matters still in dispute [1].
• Findings of fact at the joint trial will bind both sets of proceedings and all three parties [1].
• The new RICS expert witness standard (5th edition) takes effect on 30 November 2026, so surveyors preparing evidence for these dual-forum cases must meet both the court rules and the RICS standard [5].

The Dispute Behind the Judgment

Centrillion Point is a former office building in Croydon that Durkan converted into flats in the late 2000s. Wallace Estates acquired the freehold in 2014 [4].

On 4 January 2024, the FTT made a Remediation Order under section 123 of the Building Safety Act 2022, requiring Wallace to remedy specified building safety defects. On 1 July 2024, Durkan agreed under a remediation agreement to carry out the works at its own cost. The works were delayed. In June 2025, Wallace purported to terminate the agreement, and in September 2025 it applied to the FTT for a Remediation Contribution Order under section 124 against Durkan and its parent, Durkan Holdings, claiming about £13.6 million [4].

Durkan responded by suing in the TCC for declarations that the termination was unlawful. Wallace counterclaimed. In Durkan Estates Limited v Wallace Estates Limited [2026] EWHC 2003 (TCC), handed down on 30 July 2026, Constable J refused Wallace's application for reverse summary judgment. He held that Durkan's claim that the termination was unlawful had a real prospect of success and that the issues of repudiation, affirmation and estoppel needed a trial [2].

What the Joint TCC–FTT Judgment Decided

Hearing together, not consolidation

The court and tribunal agreed that the TCC and FTT proceedings should be managed and heard together, relying on CPR 3.1(2) and rule 6(3)(b) of the FTT Rules [1]. They preferred a joint hearing to formal consolidation, so each set of proceedings keeps its own identity, parties, procedural rules and judgment, while the evidence and findings are shared.

Findings of fact made at the joint trial will bind both sets of proceedings and all three parties, including Durkan Holdings, which is not a party to the TCC claim [1].

Who hears the case

The trial will be heard by a TCC judge and an FTT judge sitting together. No professional member will sit. A pre-trial review is fixed for 16 July 2027, and the trial is provisionally listed for 11 October 2027 and 31 January 2028 [1].

Disclosure and witnesses

Disclosure follows Practice Direction 57AD, the more demanding of the two regimes, so that documents are disclosed once rather than twice. The parties have express permission to use documents, witness statements and expert reports from either set of proceedings in both. A single set of witness statements of fact will serve both forums [1].

Costs and the TCC Guide

Separate cost codes are kept for FTT-only, TCC-only and joint work, with apportionment reserved for later [1]. The judgment endorsed the reasoning in section 9 of the TCC Guide, which focuses on consistent factual findings, avoiding duplicated evidence and cost, and a single or joint judicial mind. It also said that these joint-management principles can apply more broadly than the Guide's own definition of "TCC BSA proceedings" [1][3].

Expert Witness Evidence Building Safety Claims: The One-Set Rule

There will be one set of expert evidence for both proceedings, in three disciplines: architecture, fire engineering and quantity surveying. Each party has permission to rely on experts in those three fields [1].

CPR Part 35 applies to all of that expert evidence. Rule 19 of the FTT Rules applies only where it is consistent with Part 35 [1].

The directions follow the familiar Part 35 pattern:

• Experts of like discipline must hold discussions under CPR 35.12 and file joint statements of agreed and disputed matters [1].
• Expert reports are limited to matters not agreed in those joint statements [1].
• Experts must attend trial if they are not in substantial agreement on material matters, or if the other party requires them for cross-examination [1].

The expert timetable

Two features stand out: joint discussions come before reports, so experts narrow the issues first, and the quantity surveying evidence follows the technical evidence, so cost opinions rest on an agreed technical baseline.

Why Expert Witness Evidence Building Safety Claims Will Change

One duty, two forums

An expert giving evidence under CPR Part 35 owes an overriding duty to the court, which overrides any obligation to the person who instructs or pays them (CPR 35.3) [6]. Practice Direction 35 sets out what the report must contain, including qualifications, material relied on, the range of opinion and a statement of truth [6]. After Wallace Estates v Durkan, a surveyor whose report is read by both a TCC judge and an FTT judge must meet that standard once, for both.

For building surveyors and fire engineers, there is no "tribunal-lite" version of the report.

Joint statements carry more weight

Because reports are limited to matters not agreed, the CPR 35.12 joint statement becomes the central document, framing both the TCC judgment and the FTT decision.

Quantity surveyors move to the centre

Quantity surveying has its own expert track. In a Remediation Contribution Order claim of about £13.6 million, with a parallel contractual claim about who should have paid, the cost evidence may decide as much as the technical evidence, and it will be tested by cross-examination before two judges.

The RICS standard arrives at the same moment

The fifth edition of the RICS professional standard Surveyors acting as expert witnesses takes effect on 30 November 2026 [5]. RICS members giving expert evidence in cases run on this model must comply with both the Part 35 directions and the RICS standard, so engagement terms, conflict checks and report templates need reviewing before the end of November.

A Practical Checklist for Instructing an Expert Surveyor in a Building Safety Act Dispute

1. Check whether your case could be jointly managed. If there are, or may be, parallel TCC and FTT proceedings about the same building, raise joint management early. The judgment suggests the principles reach beyond the TCC Guide's own definition of BSA proceedings [1][3].
2. Instruct to the CPR Part 35 standard from the outset. Assume the evidence will be read by a High Court judge, even if the claim starts in the FTT.
3. Choose experts by discipline, not by convenience. Wallace Estates v Durkan uses three defined disciplines. Confirm that each expert's qualifications match the discipline they will speak to.
4. Plan for joint discussions before reports. Build time into the programme for a meaningful CPR 35.12 discussion and a clear joint statement.
5. Sequence cost evidence after technical evidence. Let the quantity surveyor work from the agreed technical position.
6. Align with the RICS 5th edition. Ask RICS-qualified experts to confirm they will comply with the standard in force from 30 November 2026 [5].
7. Keep disclosure in one place. Give the expert the full PD57AD disclosed record, not a tribunal-only bundle [1].

The Survey Merchant can connect parties with RICS-qualified expert witness surveyors across building surveying, fire safety and quantity surveying disciplines.

FAQ

Does the judgment mean every building safety case will now be heard by a judge and a tribunal judge together?
No. The judgment deals with the Centrillion Point proceedings and sets out how those cases will be run. It endorsed the TCC Guide's reasoning and said the principles can apply more widely, but each case will depend on its own facts [1][3].

Which rules govern the expert evidence, the CPR or the FTT Rules?
CPR Part 35 applies to all the expert evidence. FTT Rule 19 applies only where it is consistent with Part 35 [1].

Can an expert report prepared for the FTT be used in the TCC claim?
Yes. The parties have express permission to use documents, witness statements and expert reports from either set of proceedings in both [1].

Conclusion

Wallace Estates v Durkan [2026] EWHC 2133 (TCC) sets out a working blueprint for running building safety disputes that straddle the TCC and the FTT: one management track, one disclosure regime, one set of witness statements, and one set of CPR Part 35-compliant expert evidence [1]. For surveyor expert witnesses, the message is direct. Prepare every report to High Court standard, treat the joint statement as the core document, and be ready for cross-examination before two judges at once.

With site inspections due by 20 November 2026 and the RICS fifth edition in force from 30 November 2026, the next steps are clear: review your instructions, confirm your discipline, diarise the Part 35 discussion dates, and check your report template against both the Practice Direction and the new RICS standard.

References

[1] Wallace Estates Limited v Durkan Estates Limited & Anor [2026] EWHC 2133 (TCC), 10 August 2026. https://caselaw.nationalarchives.gov.uk/ewhc/tcc/2026/2133

[2] Durkan Estates Limited v Wallace Estates Limited [2026] EWHC 2003 (TCC), 30 July 2026. https://caselaw.nationalarchives.gov.uk/ewhc/tcc/2026/2003

[3] Osborne Clarke, "English TCC and FTT set out how to manage building safety claims across both jurisdictions", 27 August 2026. https://www.osborneclarke.com/insights/english-tcc-and-ftt-set-out-how-manage-building-safety-claims-across-both-jurisdictions

[4] Mayer Brown, "TCC Refuses Reverse Summary Judgment on Claim for Repudiatory Breach of Remediation Agreement", July 2026. https://www.mayerbrown.com/en/insights/publications/2026/07/tcc-refuses-summary-judgment-on-claim-for-unlawful-termination-of-remediation-agreement-for-building-safety-defects

[5] RICS, Surveyors acting as expert witnesses, 5th edition (effective 30 November 2026). https://www.rics.org/profession-standards/rics-standards-and-guidance/sector-standards/dispute-resolution-standards/surveyors-acting-as-expert-witnesses

[6] Ministry of Justice, Civil Procedure Rules Part 35 – Experts and Assessors. https://www.justice.gov.uk/courts/procedure-rules/civil/rules/part35