Building Safety Act 2022 s.135: the 30-year retrospective limitation period and PI cover
Section 135 of the Building Safety Act 2022 (BSA 2022) amended section 1 of the Defective Premises Act 1972 (DPA 1972) and inserted a new section 4B into the Limitation Act 1980. The effect is significant for anyone who has worked on a higher-risk building (HRB) or any dwelling at any point in the last three decades. Claims for breach of the DPA 1972 duty to build dwellings fit for habitation can now be brought up to 30 years after completion for works completed before 28 June 2022, and 15 years for works completed after that date.
What changed in practice
Before the BSA 2022, the limitation period under the DPA 1972 was six years from completion. A practice could close its files, run off its professional indemnity (PI) policy for a few years, and consider the exposure extinguished. Section 135 changed that. Works completed as long ago as 1992 can now be the subject of a fresh claim where the dwelling is alleged to be unfit for habitation on completion.
Who this affects
The retrospective extension reaches across most construction-adjacent disciplines. Practices reading this should consider the position set out in our architects PI insurance guide, our engineers PI insurance guide, our surveyors PI insurance guide, our quantity surveyors PI insurance guide and our design and build contractors PI insurance guide. Each of those pillars sets out how insurers are treating the extended liability in current renewal cycles.
How PI policies respond
PI is written on a claims-made basis. A claim notified in 2026 attaching to work done in 1998 is typically responded to by the policy in force when the claim or circumstance is first notified, not the policy in force when the work was completed. Two practical consequences follow.
- The current policy carries the exposure for very old work, even if the original insurer has long left the market.
- Run-off cover after a practice ceases trading must now be considered over a far longer horizon. A short three- or six-year run-off may leave a gap.
HRB and cladding
The BSA 2022 introduced separate building liability orders under sections 130 to 132, and the cladding remediation regime under section 124. Where a claim alleges contribution to a cladding or fire-safety defect on an HRB, the claimant pool is wider — the building owner, leaseholders, and (through the leaseholder protections) the freeholder may all bring claims.
Underwriting and disclosure
Insurers writing construction PI have, since 2022, asked specific questions about HRB exposure, cladding involvement, and historic dwelling work. The Insurance Act 2015 duty of fair presentation requires a commercial insured to disclose every material circumstance it knows or ought to know. A practice that worked on a cladded residential block in 2005 and did not flag it at renewal in 2026 may face an avoidance argument if a claim follows.
What to consider
Practices may want to consider the following at the next renewal:
- Whether the proposal form asks specifically about HRB and dwelling work, and whether the disclosure covers the full 30-year window.
- Whether the policy aggregate is sufficient given the wider claimant pool under the BSA 2022.
- Whether the run-off period in any retirement or succession plan reflects the new limitation horizon.
The retrospective reach of section 135 is a structural shift in construction liability. PI cover that was adequate in 2021 may need fresh attention.