Section 135 - limitation extension for defective premises

Spoke 1 of the Apex Insurance Brokers Building Safety Act 2022 hub. Read the hub first if you want the overview; this article goes deep on the single biggest change to construction PI exposure in a generation.

Plain English summary

For most of the last fifty years, a designer or contractor who built a dwelling could expect their civil liability under the Defective Premises Act 1972 ("DPA 1972") to come to an end six years after practical completion. Section 135 of the Building Safety Act 2022 ("BSA 2022") changed that.

From 28 June 2022, the limitation period for a claim under section 1 DPA 1972 is:

30 years for any cause of action that accrued before 28 June 2022 — that is, for any dwelling completed before that date. This extension is retrospective; it revives causes of action that had already become statute-barred.
15 years for any cause of action that accrued on or after 28 June 2022 — that is, for any dwelling completed afterwards. This is prospective only.

The same Act also extended section 1 to refurbishment works (via a new section 2A) and rewrote the limitation regime for section 38 of the Building Act 1984 on a similar 15-year prospective basis.

The practical effect: a 2002 residential project that the original designer thought was "off the books" in 2008 is back on the books until 2032. A 2024 project carries a tail to 2039. For a construction PI underwriter — whose product is fundamentally a tail-risk product — this changes everything about how they price and structure cover.

The legal position

Section 1 DPA 1972 — the underlying duty

Section 1(1) of the Defective Premises Act 1972 provides:

"A person taking on work for or in connection with the provision of a dwelling (whether the dwelling is provided by the erection or by the conversion or enlargement of a building) owes a duty (a) if the dwelling is provided to the order of any person, to that person; and (b) without prejudice to paragraph (a) above, to every person who acquires an interest (whether legal or equitable) in the dwelling, to see that the work which he takes on is done in a workmanlike or, as the case may be, professional manner, with proper materials and so as to be fit for habitation when completed."

The duty runs from any person who "takes on work" — covering architects, engineers, contractors and subcontractors — to the first purchaser and to every subsequent owner of the dwelling for the life of the limitation period. The duty is non-excludable (section 6(3)) and is owed in addition to any duty in contract or in tort.

The cause of action accrues on completion of the dwelling — meaning practical completion, not transfer of title. Alexander v Mercouris [1979] 1 WLR 1270 established that early. The defect must render the dwelling unfit for habitation, not merely defective — Bole v Huntsbuild Ltd [2009] EWHC 483 (TCC), aff'd [2009] EWCA Civ 1146 (CA); Rendlesham Estates plc v Barr Ltd [2014] EWHC 3968 (TCC) provided important guidance on what "fit for habitation" requires in the context of long-leasehold blocks of flats.

Section 135 BSA 2022 — the limitation rewrite

Section 135 BSA 2022 amends section 1 of the Limitation Act 1980 in its application to DPA 1972 claims and inserts a new section 4B Limitation Act 1980. The structure is:

For section 1 DPA 1972 causes of action accruing before 28 June 2022: the limitation period is 30 years from the date of accrual.
For section 1 DPA 1972 causes of action accruing on or after 28 June 2022: the limitation period is 15 years from the date of accrual.
For section 2A DPA 1972 (refurbishment works, also inserted by section 135) causes of action: 15 years prospectively.
For section 38 Building Act 1984 (civil action for breach of Building Regulations) causes of action accruing on or after 28 June 2022: 15 years prospectively. The retrospective revival under section 135 does not apply to section 38.

Section 135(5) — the human rights carve-out

Parliament was alive to the Article 6 ECHR / Human Rights Act 1998 issue raised by reviving statute-barred claims. Section 135(5) provides that the retrospective extension does not apply where it would breach a defendant's Convention rights or be incompatible with section 6 HRA 1998 — i.e. where it would amount to a disproportionate interference with the right to a fair trial. In practice the carve-out has been narrowly read by the courts and is unlikely to assist most defendants whose records of historical projects are reasonably intact.

The Court of Appeal — URS v BDW Trading

The leading appellate authority is URS Corporation Ltd v BDW Trading Ltd [2023] EWCA Civ 772. URS were the structural engineers on a number of residential developments developed by BDW (Barratt Developments). After the Grenfell fire, BDW investigated the buildings, found design defects, and carried out remediation. The original limitation periods for any DPA 1972 claim against URS had long expired. BDW then sought to bring claims against URS, relying on the retrospective effect of section 135.

The Court of Appeal held that:

Section 135 did revive statute-barred claims under section 1 DPA 1972.
The duty under section 1 DPA 1972 is owed not only to occupants but to the developer who commissioned the work — BDW could rely on it directly.
The voluntariness of BDW's remediation (it had carried out repairs before any leaseholder claim) did not break the chain of causation when seeking contribution from URS.
The fact that BDW had no continuing proprietary interest in the buildings at the time of remediation did not defeat its claim.

The Supreme Court heard the appeal and broadly upheld the Court of Appeal's analysis on the central limitation point in 2025. The detail of the appellate judgments matters — the case is now read as authority that section 135 operates as a powerful tool for developers and freeholders to pull original supply-chain participants back into the loss-allocation process.

The High Court — Naylor v Roamquest

Naylor & Others v Roamquest Ltd [2021] EWHC 567 (TCC) (and the subsequent 2022 judgment at [2022] EWHC 1591 (TCC)) addressed the scope of section 1 DPA 1972 in the context of post-Grenfell cladding defects on long-leasehold residential blocks. The court confirmed that defective cladding can amount to a section 1 DPA 1972 breach — i.e. the dwelling can be "unfit for habitation" by reason of fire safety defects in the external wall, even where the individual flats themselves are physically usable. Naylor is now routinely cited alongside Rendlesham as the foundation for cladding-related DPA 1972 claims.

Contribution claims

Section 135 does not change the Civil Liability (Contribution) Act 1978 itself, but it transforms its practical reach. A developer or freeholder who pays for remediation under a Remediation Contribution Order (section 124 BSA 2022) or under a Building Safety Fund grant condition can seek contribution from any other person liable in respect of the same damage, with limitation under section 10 of the 1980 Act running for two years from the date of judgment, settlement or award. That two-year period is independent of the underlying DPA 1972 limitation — meaning even where the section 135 30-year window is approaching its end, a downstream defendant who settles can still pursue contribution for two years afterwards.

The PI implications

The latent claims tail is now generational

PI policies are written on a claims-made basis. The historical assumption underpinning premium and reserve calculations was that the latent claims tail for residential design and construction work was, in practice, six years (subject to longer Latent Damage Act tail in negligence). Section 135 has destroyed that assumption.

A consultant working on residential projects today is buying cover against the risk that a circumstance arises tomorrow on a project completed in 1996. The pricing implications are obvious: insurers either price the long tail in (premium increase), narrow the scope of cover (exclusions and sub-limits), restrict capacity (lower limits), or all of the above. The market has done all three.

Run-off has become a much bigger problem

A traditional six-year run-off for a closing practice now offers only one-fifth of the maximum DPA 1972 limitation window. Insurers offering long-form run-off (10, 15 or theoretically 30 years) charge accordingly, and several have withdrawn the product entirely. See Spoke 8 — Run-off cover and the 30-year horizon.

Disclosure has become much harder

Insurers now expect a residential project schedule going back at least 15 years and increasingly 30. Many design practices simply do not have records of work done in the 1990s and early 2000s. The disclosure tension this creates under section 3 of the Insurance Act 2015 is real: see Spoke 7 — Proposal-form disclosure in the BSA context.

Aggregation matters more than ever

Where a single defective design has been replicated across multiple buildings — for example, a single fire engineer's report relied on across an estate, or a standard detail used on multiple blocks of flats — the question of whether claims aggregate under the wording becomes financially decisive. The market wording is not consistent and the case law is still evolving. See the aggregation hub.

Co-defendant dynamics have changed

Under the old regime, by the time a developer worked out that a building had a defect, the original consultants were often beyond limitation and the developer carried the loss alone. Under section 135, the consultants are reachable — and the developer's first instinct is to reach for them. Expect to be named in third-party proceedings, to receive Part 18 requests for documents going back to the 1990s, and to be invited to contribute towards settlements.

Worked scenario

Facts (illustrative, anonymised):

In 1999, a small architects' practice — three partners, turnover £400k, PI limit £1m — was the lead designer on a six-storey block of 24 flats in West London. Practical completion: April 2001. The practice did the usual fire stopping detailing and selected what was then a code-compliant external wall system, including aluminium composite panels.

The original partners retired progressively. Two of the three retired before 2010; the third closed the practice in 2014. The closing practice bought six years of run-off cover at the time, expiring in 2020. After 2020, no run-off was in force.

In 2024, the freeholder of the building obtained a Remediation Contribution Order under section 124 BSA 2022 against the original developer's holding company. The developer paid £4.8m towards remediation of the external wall. In 2025, the developer's solicitors wrote to the surviving former partner asserting a section 1 DPA 1972 claim and seeking contribution under the Civil Liability (Contribution) Act 1978.

Issues:

The original DPA 1972 limitation expired in April 2007. The retrospective extension under section 135 BSA 2022 puts the limitation horizon at April 2031. The claim is in time.
The original limit of indemnity was £1m. The run-off cover expired in 2020. There is no live PI policy.
The former partner has joint and several liability with the long-defunct practice (which has no assets).
The freeholder's claim against the developer was for £4.8m. The developer's contribution claim is likely to seek a significant share.

Outcome (illustrative): the former partner faces personal liability with no PI behind it. The case settles for a figure that consumes most of his retirement savings. He cannot now buy new PI cover for the past work because no insurer will retroactively underwrite a known claim.

The point: the time to plan for section 135 was the day the practice closed in 2014. The cost of long-tail run-off then was a fraction of the eventual exposure. This is now the central problem for closing or retiring construction professionals.

Sector-specific practical takeaways

Architects and multi-disciplinary practices: maintain a residential project register going back 30 years if humanly possible. Update it annually. Where original drawings are missing, document that fact in writing. Engage with insurers proactively — surprise disclosures at notification stage trigger fair-presentation arguments.

Structural and civil engineers: URS v BDW is named for a reason. Engineers are squarely within the URS class of defendants and have been a primary target of post-2022 contribution claims. Make sure your record retention covers structural calculations as well as drawings.

Fire engineers: the section 135 tail is especially severe because the work product directly determines fitness for habitation under section 1 DPA 1972. Insurance availability is narrower here than for any other discipline — see Spoke 6 — PI availability for fire safety, EWS1 and cladding.

Surveyors providing EWS1 sign-off: an EWS1 statement is a representation that can found liability not only to the commissioning party but to lenders and subsequent purchasers. Although the fitness for habitation test under section 1 DPA 1972 is not always a comfortable fit for an EWS1 review, the practical exposure remains substantial.

D&C contractors: the contractor on a residential project is a "person taking on work for or in connection with the provision of a dwelling" within section 1. The section 135 extension applies in full. See Spoke 4 — Principal Contractor exposure.

Frequently asked questions

1. Does section 135 apply to commercial buildings? No. Section 1 DPA 1972 is limited to dwellings. The section 135 retrospective extension travels only as far as the underlying DPA duty.

2. Does it apply to mixed-use buildings? The residential element is in scope. A mixed-use block with flats over commercial ground floor space has full DPA 1972 exposure in respect of the dwellings.

3. What about hotels, student accommodation and care homes? The question is whether the unit is a "dwelling" in the section 1 DPA 1972 sense. Student accommodation in cluster flats has been treated as in scope in some authorities; pure hotel rooms are not dwellings. Specialist advice is essential.

4. Did section 135 change the section 38 Building Act 1984 limitation retrospectively? No — only prospectively, on a 15-year basis. The retrospective extension under section 135 is specific to section 1 DPA 1972.

5. We were named as a defendant in 2025 on a 1998 project. How do we notify? Immediately. Notify your current PI insurer (if you are still in cover) under the "circumstances" clause as a matter of urgency. If your cover lapsed, notify any historic insurer that was on risk at the relevant time — but be aware that with a claims-made cover, only the insurer on risk at the date of notification has the obligation to respond. This is exactly the run-off problem.

6. Can we rely on the Article 6 / Human Rights Act carve-out in section 135(5)? In principle, yes. In practice, the courts have been reluctant to find a Convention breach where the defendant has reasonable records and the claim is substantively meritorious. The carve-out is unlikely to be a reliable defence.

7. What is the relationship between section 135 and the standard six-year tortious limitation under section 14A Latent Damage Act 1986? They run in parallel. Section 135 governs DPA 1972 claims; section 14A governs negligence claims for latent damage. A claimant can pursue both, and limitation is judged separately for each. The DPA claim is often the easier route because it does not require proof of fault in the negligence sense.

8. Does the DPA 1972 duty extend to subcontractors and sub-consultants? Yes — the duty is owed by any person "taking on work for or in connection with the provision of a dwelling". The chain of contribution can therefore run several layers deep, and contractors' policies routinely face claims pulling in their PI as a contribution route.

9. Can a claimant under section 1 DPA 1972 recover pure economic loss? Yes — section 1 DPA 1972 is statutory in nature and the Murphy v Brentwood economic-loss bar in the tort of negligence does not apply. This is one reason the section 1 route has become so popular post-Grenfell.

10. What is the practical limit of the 30-year retrospective window? For a building completed in, say, 1995, the DPA 1972 cause of action expired in 2001. Section 135 revived it with limitation now running to 2025. Buildings completed in 1992 or earlier may technically fall outside even the new 30-year window depending on the precise accrual date — the 30 years runs from accrual (completion), not from 28 June 2022.

Sources

Statute — Building Safety Act 2022 c.30, s.135; Defective Premises Act 1972 c.35, ss.1, 2A, 4, 6; Limitation Act 1980 c.58, s.4B (as inserted); Building Act 1984 c.55, s.38; Civil Liability (Contribution) Act 1978 c.47, s.10.

Case law — URS Corporation Ltd v BDW Trading Ltd [2023] EWCA Civ 772 (and Supreme Court onward history, 2025); Naylor & Others v Roamquest Ltd [2021] EWHC 567 (TCC); Naylor & Others v Roamquest Ltd [2022] EWHC 1591 (TCC); Rendlesham Estates plc v Barr Ltd [2014] EWHC 3968 (TCC); Bole v Huntsbuild Ltd [2009] EWHC 483 (TCC), [2009] EWCA Civ 1146; Alexander v Mercouris [1979] 1 WLR 1270; Murphy v Brentwood DC [1991] 1 AC 398.

Reports — Building a Safer Future, Dame Judith Hackitt, May 2018; Grenfell Tower Inquiry: Phase 2 Report, September 2024.

Where this fits

Disclaimer

This is legal and insurance commentary, not advice. The Building Safety Act 2022 regime is technical and fact-sensitive — consult specialist counsel and your broker on your specific position. Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority, FRN 724952.