A specialist structural engineering practice receives a letter from solicitors for the freeholder of a 22-storey residential block completed in 2009. The block's external wall system is found to contain combustible insulation behind a rainscreen; an EWS1 assessment and intrusive investigation conclude that the original design did not adequately allow for fire spread across the facade. Remediation is estimated at £14m. The claim names the original architect, the cladding sub-contractor (now in administration), the contractor (in solvent run-off and disputing liability) and the structural engineer who signed off the load-bearing aspects of the rainscreen and supporting framework. Defence costs alone will run into six figures before any apportionment is settled.
That letter, sent seventeen years after practical completion, would have been time-barred under the Defective Premises Act 1972 as it stood before 28 June 2022. Section 135 of the Building Safety Act 2022 made it live again. The structural engineer's PI policy in force when the claim is notified — not the policy in force in 2009 when the work was done — is the policy that will respond. Whether it does, and on what terms, is what this article is about.
This is a companion cluster to the Engineers PI Insurance UK Guide 2026. The pillar covers the framework; this article is the structural engineer's view of the changed claims environment, what insurers have done to their wordings, and where the firm's negotiating energy at renewal now goes.
What changed — the post-Grenfell claims trajectory
The Grenfell Tower fire of 14 June 2017 killed 72 people and triggered a multi-year reassessment of how the UK regulates building safety. The Hackitt Review of 2018 set out the case for systemic reform; the Building Safety Act 2022 enacted the principal changes, with the higher-risk-building regime and the gateways and building safety case provisions phasing in across 2023 and 2024.
For structural engineers the claims trajectory has run on three tracks. Cladding remediation claims: where the engineer was involved in the original external wall system design, the supporting framework, the fire-stopping at compartment lines, or the structural elements of any non-compliant cladding system, the freeholder's remediation claim names the engineer alongside other consultants and contractors. Typical residential block remediation in 2023-2025 has run from low-millions to tens of millions per building. Building Safety Fund and scheme recoveries: where remediation is funded through the Building Safety Fund, the Cladding Safety Scheme or developer pledges, subrogated recovery actions against the original design team are increasingly common. Pre-2022 work coming back into scope: section 135 of the Building Safety Act 2022 extended the Defective Premises Act 1972 limitation period for dwelling-related work completed before 28 June 2022 from six years to 30. Work an engineer did in the 1990s, 2000s or 2010s — time-barred when the original policy ran off — can now be the subject of a claim notified to the current policy.
The insurance market response was visible from late 2018 and accelerated through 2020-2022. Premiums for structural engineers with high-rise residential exposure rose materially; aggregate sub-limits and exclusions for cladding and fire safety became standard; retroactive dates were restricted; some insurers withdrew. By 2025-2026 the market has stabilised somewhat for firms with clean records and limited residential exposure, but the cladding, fire-safety and Building Safety Act sub-limits remain a fixed feature.
The regulatory and statutory backdrop
The Building Safety Act 2022 introduced the higher-risk-building regime (residential buildings 18m or above, or seven storeys or more, with at least two dwellings; care homes and hospitals at the same height for design and construction), the Building Safety Regulator within the Health and Safety Executive, gateways one (planning), two (pre-construction) and three (completion), the accountable person, the building safety case requirement and the golden-thread record-keeping obligation. The Defective Premises Act 1972, as amended by section 135, gives an actionable duty to any person taking on work in connection with the provision of a dwelling, with the limitation period extended to 15 years for work completed on or after 28 June 2022 and 30 years for work completed before. The retrospective effect is what has changed the landscape.
Building Liability Orders under section 130 allow the High Court to extend liability for a "relevant liability" of a body corporate to any associated company where it is just and equitable. Remediation contribution orders under section 124 allow the First-tier Tribunal to order developers, landlords and associated parties to contribute to remediation costs, with effects that flow through to engineers via the contractual chain. The Construction (Design and Management) Regulations 2015 continue to allocate duties between client, principal designer, principal contractor, designers and contractors; the Building Safety Act regime sits on top, with the higher-risk-building gateway-two roles distinct from the CDM equivalents though commonly held by the same parties.
IStructE has issued practice guidance on the Building Safety Act for structural engineers — the firm's role in the structural elements of the building safety case, structural input to fire engineering assessments, and the golden-thread documentation expectations. Approved Document B sets the technical fire-safety standards; the post-Grenfell revisions, including the ban on combustible materials in external walls of relevant buildings under Regulation 7(2), underpin much of the current cladding remediation.
What insurers have done to the wordings
Standard structural engineers' PI policies in 2025-2026 carry a recognisable set of wording features in response. Cladding and external wall system sub-limits or exclusions — where the engineer's work involved external wall systems on residential buildings, the policy commonly carries a sub-limit (£250,000, £500,000, £1m, or 10-20% of the headline limit are typical) and a separate aggregate within the policy year; some policies exclude cover entirely for work on buildings above 18m completed after a specified date. Fire safety and fire engineering sub-limits sit alongside. Building Safety Act-specific sub-limits or aggregates carve out claims engaging Building Safety Act duties into a separately-aggregated bucket. Restricted retroactive dates — on accounts with claims history or material residential exposure, retroactive dates have been tightened. Higher excesses on relevant claims — a standard each-and-every excess of £10,000 may be accompanied by a £100,000 or £250,000 cladding excess. Notification obligations on higher-risk-building projects — some policies require notification when the firm takes on a higher-risk-building appointment.
The headline limit may be unchanged from a 2017 policy; the cover available for the claims actually being made will be materially different.
Where claims are coming from
Working from anonymised industry patterns through 2024-2026, structural engineers' Building Safety Act-related claims cluster around original external wall system design (structural backing, fire-stopping at compartment lines, support brackets for rainscreen, facade-to-primary-structure integration) — the structural element may be a small proportion of the total remediation but the engineer is in the claim and bearing defence costs proportionate to the whole; EWS1 and intrusive survey work, where the firm carries direct exposure to the survey opinion; building safety case structural input, where errors can trigger claims if the case fails to satisfy the Building Safety Regulator; principal designer appointments under the gateways, where a refused gateway or withdrawn approval can ground a claim for delay and abortive cost; pre-2022 residential work newly in scope under the retrospectively-extended Defective Premises Act; and recovery and subrogation claims following Building Safety Fund or developer-pledge remediation.
Claim values vary. The structural engineer's share of a £14m cladding remediation may settle at a few hundred thousand pounds after apportionment; the share of a £500,000 single-block remediation may run to most of that figure. Defence costs frequently exceed the eventual settlement on multi-party disputes.
Run-off — the 30-year problem
For a structural engineering practice considering closure, retirement or sale the run-off decision is now materially more complex than it was in 2017. The standard limitation periods remain: six years for ordinary breach-of-contract claims, twelve where the contract was executed as a deed, six years from latent damage being reasonably discoverable under the Latent Damage Act 1986. To these the Defective Premises Act 1972 (as amended) adds 15 years for dwelling-related work completed on or after 28 June 2022 and 30 years for work completed before.
A practice with substantial historic residential exposure retiring in 2026 is theoretically exposed to claims for work going back to 1996. Buying run-off to the full theoretical limit is possible in principle but in practice the market for 30-year run-off on past residential work is thin and expensive. The decisions a closing practice has to take include how much past dwelling-related work the firm has and where; whether the current policy's retroactive cover reaches the start of that work; whether run-off can be placed at a duration that meaningfully matches the longest theoretical claim; and whether the firm has the warranty register the run-off underwriter will ask for. The honest answer for many practices is that available run-off does not match the theoretical exposure under section 135; where that gap exists, the firm needs to be clear-eyed about it, particularly where partners' personal assets stand behind the firm.
What to ask at renewal
The areas worth working through with the broker each year are whether the cladding, fire-safety and Building Safety Act sub-limits are consistent with the work the firm is taking on; whether the retroactive date is continuous with previous cover; what the aggregate cap is on cladding, fire-safety and Building Safety Act claims and how many open notifications sit against it; whether the policy requires notification of higher-risk-building appointments; and whether the wording is structural-engineer-specific or a general consulting engineer wording with a structural endorsement.
A submission that lets underwriters price the structural engineer's risk sensibly typically covers fee income by sector (residential split into low-, mid- and high-rise; commercial; healthcare; education; industrial; infrastructure); the largest live projects and the largest completed in the last three years; higher-risk-building appointments and the gateway status of each; the firm's role on each (lead designer, design check, principal designer, fire engineer); procedures (peer review, supervision, calculation verification, golden-thread record-keeping); the five-year claims and notifications history; and the collateral warranty register.
How Apex helps
Apex acts for structural engineering practices through the size range from sole practitioners to mid-tier consulting firms. We place PI cover on a non-tied basis with the FCA-authorised insurers we believe will price the particular firm's profile sensibly, and we negotiate the wording and the sub-limits — particularly the cladding, fire-safety and Building Safety Act provisions — rather than accepting the standard offer as given. We are not the firm's lawyer and we do not draft appointments, but we sit alongside the firm in the renewal and appointment-review conversation and bring the insurance perspective: which provisions are insured under the firm's policy, which are not, and where the firm is being asked to take on uninsured contractual exposure.
The terms on which we act are set out in our Terms of Business, our handling of personal data in our Privacy notice, and the route to raising any concerns on our Complaints page. The engineers sector page is the place to start the renewal conversation, or contact us directly.
Frequently asked questions
Does my PI policy cover claims arising from cladding work I did before Grenfell?
It depends on the retroactive date on the policy in force when the claim is notified, the cladding-related sub-limits in that policy, and the aggregate position at notification. Most policies in force in 2026 have cladding sub-limits. A headline £5m limit may have a £500,000 cladding aggregate across the policy year. Wording detail matters more than the headline.
What is section 135 of the Building Safety Act and why does it matter?
Section 135 extended the Defective Premises Act 1972 limitation period for dwelling-related claims to 30 years retrospectively for work completed before 28 June 2022 and 15 years prospectively for work completed after. The retrospective extension brought historic residential work back within scope. Structural engineers with residential portfolios going back decades face exposure their previous insurance was never priced for.
Are insurers still writing structural engineers' PI for firms with high-rise residential exposure?
Yes, but more selectively than before 2017-2018. Cladding, fire-safety and Building Safety Act sub-limits and aggregate caps are standard; some insurers require notification of each higher-risk-building appointment; some have withdrawn. Firms with clean claims histories and mature procedures generally find cover available.
What is an EWS1 form and what is the PI exposure?
The External Wall System (EWS1) form was introduced in December 2019 by RICS with mortgage lenders as a standard way of recording a fire-safety assessment of an external wall system on residential buildings above 18m (subsequently extended to 11m). Engineers acting as the EWS1 signatory carry direct exposure to the assessment's accuracy. PI cover is available but underwriting is detailed; some policies sub-limit it.
What is a building safety case and how does it affect structural engineers?
The building safety case is the documented justification, required for occupied higher-risk buildings, that risks are being managed by the accountable person. Structural input forms part of the case; engineers contributing it carry exposure to its accuracy. Where the Building Safety Regulator directs remediation, the engineer's input may be reviewed and challenged.
How long should I hold run-off cover for past residential work?
The theoretical maximum under section 135 is 30 years for residential work completed before 28 June 2022 and 15 years for work after. Run-off at the full 30-year mark is rare and the market narrow. The decision needs to consider the firm's actual back-catalogue, the retroactive position of the run-off, the cost, and the partners' tolerance for residual personal exposure.
Does my PI policy cover principal designer duties on a higher-risk-building project?
Most current policies cover principal designer duties as part of the firm's professional activities, but the schedule should be checked. Some policies sub-limit Building Safety Act-specific duties or require notification of higher-risk-building appointments. The principal designer role under the Building Safety Act gateways is distinct from the CDM principal designer role; both should be checked.
Can I refuse to sign appointments that require cover beyond what my policy provides?
You can negotiate, and you can decline. Where the client insists on cover the firm does not have, project-specific PI for the duration of the project is sometimes available at additional premium. The broker's role is to make the insurance position clear so the commercial decision can be made on its merits.
Related guides
- Engineers PI Insurance UK Guide 2026 (pillar)
- Consulting engineer PI and collateral warranties
- Engineers sector page — speak to a broker
- All Apex PI sectors
About Apex Insurance Brokers
Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority, FCA firm reference 724952. Registered in England and Wales, Companies House 07014570. Trading address QCS, 53 Queen Charlotte Street, Bristol BS1 4HQ; registered office c/o Westcan, 5 Anglo Office Park, Bristol BS15 1NT. Email info@apexinsurancebrokers.co.uk, telephone 0117 325 0027. This article is general information about Professional Indemnity Insurance for UK structural engineering practices and is not advice tailored to any individual firm's circumstances. Last reviewed: May 2026.
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