The Building Safety Act and professional indemnity insurance

What the Act actually changed for design professionals

The Building Safety Act 2022 is a long piece of legislation and most coverage of it has focused on high-rise residential buildings and remediation. For an SME architect, engineer, surveyor or design-and-build contractor, three strands matter more than the rest.

The first is limitation. Section 135 of the Act inserted a new section 4B into the Limitation Act 1980 and took effect on 28 June 2022. For claims under section 1 of the Defective Premises Act 1972 accruing on or after that date, the limitation period is 15 years. Where the right of action accrued before that date, the period is 30 years. That is an extraordinary reach into completed work.

The second is the dutyholder regime. The Building Regulations etc. (Amendment) (England) Regulations 2023 created principal designer and principal contractor roles under the Building Regulations from 1 October 2023, with the transitional arrangements ending on 6 April 2024. These are competence-based roles carrying responsibility for Building Regulations compliance, and they apply to most projects — not only higher-risk buildings.

The third is the higher-risk building regime itself: a separate building control route through the gateways, run by the Building Safety Regulator, with formal appointments and record-keeping that leave a durable documentary trail of who was responsible for what.

Why claims-made PI and retrospective liability collide

This is the point that matters most, and it is the one clients most often have not thought through.

Professional indemnity insurance is written on a claims-made basis. The policy that responds to a claim is the policy in force on the day the claim is first made against you and notified — not the policy that was in force when you did the work. There is no bank of old policies to fall back on. The wording, the limit, the excess and, crucially, the exclusions are those of the current year.

Now put that alongside a liability that can reach back many years. A claim arising from a specification written a decade ago is made against a policy bought this year. If that policy carries a fire safety or cladding exclusion — and many construction PI policies now do — the exclusion applies to the old work, even though nothing like it existed when the work was done. The practice was insured at the time. It may not be insured now for the same act.

That asymmetry is the single most important thing for an SME construction professional to understand about the Act. It is also why a broker conversation is worth having before renewal rather than after a notification.

URS v BDW: what the Supreme Court confirmed

In URS Corporation Ltd v BDW Trading Ltd [2025] UKSC 21, handed down on 21 May 2025, the Supreme Court dealt with several questions arising from this new landscape. Read carefully, it made the exposure broader rather than narrower.

The Court held that the extended limitation periods introduced by section 135 are not confined to claims brought under the Defective Premises Act itself; they apply also to negligence and contribution claims that depend on those time limits. It held that the duty under section 1 of the Defective Premises Act can be owed to a developer that ordered the work, not only to eventual purchasers or occupiers. It rejected a blanket rule that a party which carried out remedial work voluntarily, without being legally compelled, can never recover the cost — recoverability turns on ordinary questions of causation and reasonable mitigation. And it held that a contribution claim under the Civil Liability (Contribution) Act 1978 can arise where a party has effectively paid compensation in kind by carrying out remedial works, without first needing a judgment or a settlement with a third party.

The practical translation for a small consultancy is straightforward: a developer or main contractor that has fixed a defect at its own cost has a clearer route to come looking for a contribution from the designers and specialists who worked on the building, and a longer period in which to do it.

What underwriters are asking now

Underwriters have responded to all of this the way underwriters do — with questions, and with wording. On a construction-sector PI renewal, expect to be asked about the sectors and building types in your past work as well as your current work, because the liability is retrospective. Expect specific questions about any involvement with external wall systems, cladding, insulation, render, curtain walling and fire-stopping, and about high-rise or higher-risk residential work at any point in the practice’s history.

Expect questions about whether the practice takes, or has taken, the principal designer role under the Building Regulations, and how it satisfies itself on competence for that role. Expect questions about appointment documentation, net contribution clauses, collateral warranties given, and reliance letters issued. And expect to be asked about record retention — because on a fifteen or thirty year horizon, the practice that can produce its drawings, decisions and correspondence is in a materially better position than the one that cannot.

None of this is bureaucracy for its own sake. The quality of these answers is what separates a risk an underwriter can price from one they decline.

Where run-off fits in

A practice that closes, retires or is sold does not shed this exposure. Because PI is claims-made, a claim made after the practice stops trading needs a policy in force to respond to it — and that is what run-off cover is. Against a liability period measured in decades, the question of how long run-off should be maintained, and what it will cost in later years, is a real financial planning issue rather than a formality.

It is dealt with in more detail on our page on Defective Premises Act limitation and PI cover.

What Apex can and cannot do

We should be plain about this. Fire safety and cladding exclusions are common in the construction PI market and no broker can promise to remove them. Anyone who tells you otherwise is selling something.

What a broker can do is make sure your risk is presented accurately and completely to markets that understand construction professionals: your real sector mix, your real involvement (or lack of it) with external wall systems, the controls and appointment discipline you actually have, and the record-keeping that supports it. Firms are routinely priced as though they carry risks they do not carry, simply because the proposal form did not give them room to say so. Accurate presentation is worth money, and it is worth more each year that the liability tail gets longer.

Frequently asked questions

Does my professional indemnity policy cover work I did before the Building Safety Act?

It depends on the policy in force when the claim is made, not the one in force when the work was done. PI is claims-made, so an old piece of work is judged against today’s wording, today’s limit and today’s exclusions. If your current policy carries a fire safety or cladding exclusion, that exclusion can apply to historic work that predated it.

How far back can a Defective Premises Act claim reach?

Section 135 of the Building Safety Act 2022 inserted section 4B into the Limitation Act 1980 with effect from 28 June 2022. For claims under section 1 of the Defective Premises Act 1972 accruing on or after that date the period is 15 years. Where the right of action accrued before that date, the period is 30 years. This is a general description of the legislation, not legal advice on your position.

Do I need to tell my PI insurer about historic high-rise work?

You need to answer your insurer’s questions fully and accurately, and construction PI proposal forms now ask about historic building types, external wall systems and higher-risk residential work. Because the liability is retrospective, past work is material to the risk being underwritten. Incomplete disclosure is a far bigger problem than an awkward answer.

Is professional indemnity insurance compulsory for architects and engineers?

It depends on the profession and the appointment. Some professional bodies require it of their members and many client appointments require it as a contractual condition, often with a specified limit and a specified period after completion. Check both your professional body’s rules and the terms of each appointment, because the appointment often demands more than the minimum.

This page is insurance information for UK businesses, not legal or regulatory advice. It describes how the Building Safety Act landscape is affecting professional indemnity cover and what underwriters are asking; it does not tell you how to comply with the legislation. For advice on your duties under the Act, take specialist legal advice. Position stated as at August 2026.

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