Consulting engineers’ PI insurance: the 2026 appointment and design-risk guide
Design liability: skill and care, not a guarantee
An engineer’s implied obligation at common law is to exercise the reasonable skill and care of a reasonably competent engineer in the relevant discipline. Professional indemnity insurance is built around exactly that standard. An appointment that instead requires the design to be fit for a stated purpose imposes a strict obligation that does not depend on fault, and strict obligations of that kind commonly fall outside a PI wording — the reasoning is set out on our breach of contract cover page.
The practical position for 2026 is unchanged in principle and tighter in practice: negotiate fitness-for-purpose language down to reasonable skill and care, and where a client insists, escalate it rather than absorbing it. The same applies to performance warranties, compliance warranties expressed absolutely, and design-and-build obligations passed down from a contractor’s own strict duty.
Net contribution clauses
Where several consultants and contractors contribute to a defect, English law would ordinarily leave each of them jointly and severally liable to the employer for the whole loss, with contribution between them sorted out afterwards under the Civil Liability (Contribution) Act 1978. If a co-defendant is insolvent, the solvent consultant carries the shortfall.
A net contribution clause addresses that by limiting the consultant’s liability to the share that is just and equitable having regard to the responsibility of others, on the assumption those others have paid their share. The Court of Appeal considered such a clause in West v Ian Finlay & Associates [2014] EWCA Civ 316, upholding the clause in the architect’s terms on the construction of the contract as a whole and reversing the first-instance decision. The case is the standard reference point, and its practical lesson is about drafting: the clause has to be clear, and it has to sit comfortably with the rest of the appointment.
A net contribution clause does not extend your insurance. It reduces the number your insurer may have to fund, which is why insurers welcome it and why it is worth defending in negotiation.
Collateral warranties and third-party rights
Funders, purchasers and tenants routinely require collateral warranties from the design team, and the standard package can run to a dozen or more per project. Each one is a fresh contract creating a fresh duty to a party you have never advised, often with its own limitation period running from its own date.
Three terms decide how much extra exposure a warranty really adds. Whether the standard of care is no more onerous than the appointment — the “no greater liability” provision. Whether the number of assignments is capped. And whether the insurance obligation in the warranty mirrors the appointment rather than adding to it. Our page on collateral warranties and your PI programme works through the drafting; note also that where third party rights are used instead of warranties, the same questions apply to the schedule of rights.
What JCT and NEC appointments require
Both major standard-form families deal with professional indemnity in broadly the same shape, and the detail is in the project-specific data rather than the printed conditions.
Expect the contract particulars or contract data to state the required amount of cover, the basis on which it is required — each claim or in the aggregate, a distinction covered on our each and every claim page — and the period for which cover must be maintained after completion, commonly a number of years running from practical completion. Expect an obligation to maintain the cover provided it remains available at commercially reasonable rates, with a duty to notify the other party if it ceases to be so available so the parties can discuss how to protect their positions.
Three points catch practices out. First, the maintenance period is a run-off commitment: if you close, merge or sell, you have already promised to keep cover in place, which is why the run-off decision should be made against the contract register rather than in the abstract. Second, an aggregate requirement and an each-and-every schedule are not interchangeable, and a certificate that does not match the requirement can hold up payment or a funding drawdown. Third, where the appointment demands specific cover for asbestos, pollution, fire safety or cladding, check the schedule for inner aggregates and exclusions before certifying compliance.
Fire safety, cladding and the Building Safety Act
The single largest change in engineering PI underwriting since 2022 is the treatment of fire safety and external wall risk. Fire safety and cladding exclusions became widespread across the construction professional indemnity market, and although the market has eased in places, the exclusions remain common and vary considerably in width. Some bite only on external wall systems on higher-risk buildings; others reach any allegation involving fire safety in any building of any height. Reading the specific words is not optional — see fire safety and cladding exclusions.
The legal backdrop is the Building Safety Act 2022. Section 135 of that Act inserted section 4B into the Limitation Act 1980, setting a 15-year limitation period for claims under section 1 of the Defective Premises Act 1972 accruing after commencement on 28 June 2022, and applying a 30-year period retrospectively to rights of action that had accrued before that date, subject to transitional protection. For engineers, the practical effect is a very long tail on residential work, at a time when policies are written on a claims-made basis and cover has to be maintained rather than assumed. Our pages on the Building Safety Act and PI, Defective Premises Act limitation, higher-risk buildings and principal designer duties cover the regime in more depth.
What underwriters ask engineering practices in 2026
Expect questions built around discipline split and project type, not just fee income: the proportion of civil, structural, geotechnical, M&E and fire engineering work; residential versus commercial; any work on buildings above the higher-risk threshold; any external wall or cladding involvement, historic as well as current; the largest single project value and the largest contract value where you carry design responsibility; how much work is design-and-build with liability stepped down from a contractor; and your policy on signing collateral warranties and accepting fitness-for-purpose terms. Every submission Apex makes carries a named broker, and our page on where a specialist engineers PI broker adds value sets out what that means in practice.
Practices that answer these precisely, with a contract register and a clear statement of what they will and will not sign, present better than those that answer in generalities. A good presentation is also a fair presentation obligation, not merely a marketing exercise.
Setting the limit
For engineering practices the limit question is rarely answered by fee income. The exposure is the cost of correcting the element you were responsible for, which on a structural or facade issue can dwarf both your fee and, in remediation cases, the original cost of the works. Add the aggregation question — a repeated detail across a portfolio of similar buildings — and the case for an each-and-every-claim basis with defence costs in addition becomes clear where it is available. Our limit-sizing framework sets out the steps.
Frequently asked questions
How is this different from your main engineers’ PI page?
The main page explains the cover itself — what an engineering practice needs, how the policy is built and how we place it. This guide is contract-led: it works through the appointment terms, warranties, standard-form insurance clauses and Building Safety Act exposure that decide whether the cover actually answers when a claim arrives. Most practices need both.
Can we agree a fitness-for-purpose obligation if the client insists?
You can agree it, but it is commonly outside a professional indemnity wording because it imposes liability without fault. If it cannot be negotiated back to reasonable skill and care, raise it with your broker before signing so the exposure is at least identified and, where possible, discussed with underwriters rather than discovered during a claim.
Do net contribution clauses actually work?
The Court of Appeal upheld a net contribution clause in West v Ian Finlay & Associates [2014] EWCA Civ 316, reversing the decision below, on the construction of the appointment as a whole. Whether any particular clause works depends on its drafting and the surrounding terms, so it is worth using clear, tested wording rather than an ad hoc formulation.
How long do we have to keep PI cover after a project finishes?
Whatever your appointments and warranties say — standard-form contract particulars typically specify a number of years running from practical completion, and warranties can add their own periods. Because Building Safety Act changes extended limitation for Defective Premises Act claims well beyond that, the contractual period is a floor rather than a full answer to how long real exposure lasts.
This page is general insurance information about how UK professional indemnity policies are commonly structured. It is not legal advice, and it is not a statement of what any particular policy covers. If a claim, a circumstance or a contract term is in issue, read your own wording and take advice on your own facts.
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.