Aipedia: Architects

Architects, AI and structural calculations: lessons from CROSS 1554

Aipedia, by the Apex broking team · Last reviewed 2026-10-27

Architects should not use AI to produce structural calculations they are not competent to check. CROSS-UK Report 1554 shows how an unverified AI calculation can create a real safety risk and a competence breach.

Part of: AI in Architects

In short

In CROSS-UK Report 1554 (16 July 2026), an architect submitted a calculation report, which the reporting engineer believed was largely AI-written, to justify heavy rooftop plant on an existing flat-slab concrete building. It had fundamental errors and an overloading risk, and no competent structural engineer had verified it. The panel cited Part 2A competence duties (regs 11F to 11H). Architects Code Standard 3.1 requires work within competence. Work outside the practice's competence or declared activities can also create a PI coverage problem.

What happened in CROSS-UK Report 1554

CROSS-UK Report 1554, "Inappropriate use of artificial intelligence (AI) in structural design", was published on 16 July 2026. An architect submitted a calculation report to justify placing heavy rooftop plant on an existing reinforced concrete flat-slab building, with retail on the lower floors and flats above.

The structural engineer who reported it was confident the calculation was largely AI-written. It contained fundamental errors and an overloading risk. No competent structural engineer had verified it, and the architect dismissed the engineer's comments.

The CROSS panel cited the Building Regulations Part 2A competence duties on architects and engineers, regs 11F to 11H, and said designers should disclose AI-assisted outputs in engineering submissions. It is a safety report, not a disciplinary or court finding, but it is the clearest UK statement so far about AI in an architect's work.

Why this is a competence issue

Architects Code Standard 3.1: work within the limits of competence. A tool that produces an output in another discipline does not extend the architect's competence to check it.
Standard 3.4: check the competence of anyone engaged on the architect's behalf. Relying on AI in place of a structural engineer skips that step.
Part 2A, regs 11F to 11H: designers must have the skills, knowledge, experience and behaviours for the work, and organisations the capability.
Reg 11K: designers must ensure their design would comply if built.

The ARB and RIBA guide covers Standard 3 in more detail.

What can go wrong

Illustrative scenario. On a small refurbishment, a client asks the architect to confirm a new roof terrace can go on an existing timber roof without appointing an engineer. The architect uses a generative AI chatbot to produce load calculations and issues them. The roof deflects after completion and needs strengthening. The client claims repair and relocation costs, and the architect's insurer asks why structural design was being done in-house.

Beyond safety, the practice now faces two questions: was the work negligent, and was it within the activities declared to insurers. Engineers face the same issues from the other side, as the engineers' guide to AI calculations explains.

Why work outside competence is a PI problem

Architects' PI usually responds to negligence in the professional services the practice declared, subject to the wording. Problems arise where:

the policy defines the professional business as architecture and the work was structural engineering, so cover for that work may be disputed;
structural or engineering work was not disclosed on the proposal form, raising fair presentation questions;
the claim is limited by scope of duty, because the architect assumed responsibility for advice it was not engaged or competent to give.

See scope of duty in architect PI claims. ARB's PII guidance requires cover that is adequate and appropriate for the work actually done.

Practical controls

Do not issue structural calculations unless the practice has engineering competence.
Where loads change on an existing building, recommend appointing a structural engineer in writing.
If AI helped prepare any engineering-related output, say so and have it verified.
Take engineers' comments seriously and record how they were resolved.
Tell your broker if the practice offers any engineering services.

How Apex helps

Apex arranges PI for architects and multidisciplinary practices. A broker can check that the services your practice actually provides, including any engineering input, are described correctly to insurers.

Sources

Frequently asked

Can an architect use AI to do structural calculations?

Only where the architect is competent to check the result, which is rare. Standard 3.1 requires work within competence, and CROSS-UK Report 1554 shows the risk of issuing unverified AI calculations. The safer course is to appoint a structural engineer.

Was the architect in CROSS 1554 disciplined?

Not as far as is known. CROSS reports are anonymous safety reports, not disciplinary findings. As at October 2026 no ARB decision or court judgment about an architect's AI use had been verified.

Should I disclose AI use to the engineer or building control?

The CROSS panel said designers should disclose AI-assisted outputs in engineering submissions, and that approving authorities may wish to ask how far AI contributed. Telling the engineer and building control where AI shaped any structural input is the prudent course.

Will PI cover structural advice given by an architect?

It depends on how the policy defines the professional business and what was declared. If the practice did not disclose engineering work, an insurer may question cover. Check the policy wording and tell your broker about any such services.

Check your PI covers how you use AI

Tell us about your firm and the work you do. A broker will review how your current PI treats AI-assisted work, or arrange new cover. No fee for a quote. Or call 0117 325 0027.

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Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority. Registered in England and Wales, company number 07014570. This page is general information about how AI is used in the profession and how insurance may respond. It is not legal, regulatory or insurance advice on your circumstances, and it does not guarantee that cover will be available or on what terms.