The long tail of liability: what the Building Safety Act means for your PI cover

Reviewed by Apex Insurance Brokers · Published 2026-08-17

If you are an architect, engineer, surveyor or any other professional whose advice shapes what gets built, the ground under your professional indemnity (PI) cover shifted in 2022 — and the full weight of it is still working through the market. The Building Safety Act 2022 did many things, but two of them matter enormously for your insurance: it reached back in time to revive claims that had long since expired, and it extended the window for future claims well beyond what most professionals had planned around. The result is a much longer “tail” of potential liability, and PI insurance is the thing that has to carry it.

What the Building Safety Act changed about limitation

The relevant provision is section 135 of the Building Safety Act 2022, which came into force on 28 June 2022. It inserted a new section 4B into the Limitation Act 1980 and transformed the limitation periods for claims under the Defective Premises Act 1972 — the Act that imposes a duty on those who take on work in connection with the provision of a dwelling to do that work properly, with proper materials, so that the dwelling is fit for habitation.

Before June 2022, a claim under section 1 of the Defective Premises Act had to be brought within six years of the dwelling being completed. Section 135 replaced that with two dramatically longer periods. For causes of action that had already accrued when the Act commenced, the limitation period became 30 years, applied retrospectively. For causes of action arising after commencement, it became 15 years, running forward. In plain terms, work signed off decades ago — and long thought to be safely beyond challenge — can, in the right circumstances, be litigated again.

The Act also widened what can be claimed. A new section 2A of the Defective Premises Act extends the duty to work done to existing dwellings, capturing refurbishment and remedial projects, not just original construction; that head of claim runs on the 15-year prospective period. And section 38 of the Building Act 1984, which creates civil liability for breach of the Building Regulations, carries a 15-year forward limitation period under the same reforms. The retrospective 30-year reach is the headline, but it is the original-construction duty under section 1 that carries it; the newer routes look forward rather than back. The courts have since confirmed that the retrospective provisions operate as Parliament intended, so this is settled ground, not a theoretical risk.

Why a longer tail is a PI problem, not just a legal one

To see why this matters so much for insurance, you have to remember how PI cover works. Almost all professional indemnity policies are written on a claims-made basis. The policy that responds to a claim is not the one that was in force when you did the work, or when the defect first existed — it is the policy in force when the claim is first made against you and notified to insurers. A design decision taken in 2010 that surfaces as a claim in 2030 is dealt with by your 2030 policy.

That is why the length of the liability tail is fundamentally an insurance question. Every extra year in which someone can bring a claim is an extra year in which you need live PI cover, or run-off cover, to meet it. Stretching the outer limit from six years to as much as thirty does not just add legal exposure — it adds many more years across which you must keep a policy in place and hope the terms available in that future year are broad enough to respond. You are, in effect, relying on the insurance market of a decade or two from now to cover decisions you are making today.

This is also why run-off cover has become more important, not less. If your practice closes, merges or is sold, claims-made cover stops responding the moment the policy lapses — yet under the new limitation regime, claims can still arrive many years after you have stopped trading. Run-off is the bridge across that gap, and the longer the tail, the longer the bridge needs to be.

Fire safety exclusions: the other half of the squeeze

The extended tail would be manageable if cover were freely and broadly available. For a stretch of the market it has not been. In the wake of the Grenfell Tower fire in 2017 and the scrutiny of external wall systems that followed, many PI insurers introduced fire safety exclusions into policies for construction professionals — carve-outs for claims arising from cladding, external wall systems or the fire performance of a building. The precise wording varies from insurer to insurer, and the breadth of these exclusions has been a live issue for professional bodies including the RIBA and RICS, which have pressed for cover that better reflects the risks their members actually face.

Put the two developments side by side and the pressure is obvious. The Building Safety Act widens and lengthens the exposure; fire safety exclusions can narrow the cover available to meet exactly the kind of claim the Act is designed to enable. A professional could hold a current PI policy and still find that a fire-related allegation about a building they worked on falls into an exclusion. That is not a reason to despair — the market has continued to evolve, and terms differ significantly between insurers — but it is a powerful reason to read your policy wording carefully rather than assuming “I have PI, so I am covered.”

What to do about it at your next renewal

You cannot shorten the limitation period — that is now set by statute. But you can manage how well your insurance meets it. A few practical steps:

• Read your fire safety wording. Find out whether your policy carries a fire safety or external wall exclusion, and exactly how it is drafted. A blanket exclusion and a narrow, defined one are very different animals.
• Map your real exposure. Think about the buildings you have worked on that could now fall within the extended periods — particularly dwellings, and particularly anything involving external walls or fire performance — and make sure your broker understands that history.
• Notify circumstances promptly. On a claims-made policy, a circumstance that might give rise to a claim should be notified to your current insurer as soon as you become aware of it. Notifying under the right policy is often what secures cover for the eventual claim.
• Plan run-off before you need it. If retirement, sale or closure is on the horizon, factor the cost and length of run-off cover into that decision now, given how long claims can now take to surface.
• Do not let cover lapse casually. Because the policy that answers is the one in force when the claim arrives, a gap in cover in any future year is a gap in protection for decades of past work.

None of this is a counsel of alarm. The point is simply that the Building Safety Act has changed the arithmetic of professional risk for anyone who works on buildings, and the sensible response is to make sure your PI arrangements — limit, wording, exclusions and run-off planning — are built for the longer tail rather than the shorter one they may once have assumed.

Frequently asked questions

Does the 30-year period mean anyone can sue me over any old project?
No. The 30-year retrospective period attaches to claims under section 1 of the Defective Premises Act 1972 — broadly, work connected with the provision of a dwelling that left it unfit for habitation. A claimant still has to establish that duty and a breach of it. What has changed is that the time bar, which used to close the door after six years, now stays open far longer, so the door being open is no longer the obstacle it once was.

If the work was done years ago, doesn't my old insurer deal with it?
Generally not. PI is claims-made, so the policy that responds is the one in force when the claim is first made and notified — not the one you held when you did the work. That is precisely why keeping continuous cover, and arranging run-off if you stop trading, matters so much under the extended limitation regime.

I am not a construction professional — does this affect me?
The limitation changes are specific to defective-premises and building-regulations claims, so they bite hardest on architects, engineers, surveyors, contractors and similar roles. But the underlying lesson — that a claims-made policy is judged by the terms available when a claim arrives, sometimes long after the work — applies to every profession that buys PI cover.

Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority (FRN 724952). This article is general information, not advice on a specific policy.