Aipedia: Quantity surveyors

AI reinstatement cost assessments: underinsurance and reliance

Aipedia, by the Apex broking team · Last reviewed 2026-10-30

A quantity surveyor can use AI to produce desktop reinstatement cost assessments, but a figure that is too low can leave a building underinsured and the owner short on a claim. Owners, managing agents and leaseholders rely on these figures for years, so errors are a common source of QS PI claims.

Part of: AI in quantity surveying

In short

Reinstatement cost assessments (RCAs) set the sum insured for buildings insurance. AI and desktop tools now generate RCAs from floor areas, building type, location and cost data, sometimes without an inspection. If the figure is too low, the insurer may apply average or otherwise reduce a claim, and the owner looks to the surveyor who produced it. The RICS AI standard requires supplier due diligence (4.1) and a named surveyor's written reliability decision with dip sampling of automated outputs (4.2). RCA claims are usually handled as negligence under RICS-compliant PI, subject to the terms.

How AI is used in RCAs

An RCA estimates what it would cost to rebuild a building after total loss, including demolition, site clearance, professional fees and compliance with current regulations. Traditionally a QS or building surveyor inspects, measures and prices it. Desktop RCAs replace the inspection with data: floor areas from plans or mapping, building type, construction and location, priced from a cost database. AI tools now go further, estimating floor areas and construction type from imagery and producing large numbers of assessments automatically for portfolios, blocks of flats and managing agents.

Our explainer on buildings underinsurance and reinstatement cost covers how the sum insured works.

The duties that apply

The main duties that apply are:

RICS AI standard 1.2: an RCA is advice the client relies on to set cover, so the tool is likely to have a material impact; record that in writing.
4.1: ask the supplier in writing how floor areas and construction types are derived, what cost data is used and how up to date it is.
4.2: a named, appropriately qualified surveyor decides whether each RCA is reliable; for high-volume portfolios, dip sampling is expected.
4.3: tell clients in advance that the assessment is AI or desktop based.
Rules 2 and 3: the RICS Rules of Conduct require competence and diligent service.

What can go wrong

Errors tend to follow a few patterns:

Floor areas taken from imagery miss basements, extensions or upper floors.
Construction type is guessed wrongly, for example listed or non-standard construction priced as conventional.
Demolition, access, professional fees or regulatory upgrade costs are left out or understated.
Cost data is out of date or not adjusted for location.
The figure is reused for years without review while rebuilding costs change.

Illustrative: a managing agent commissions desktop RCAs for a portfolio of residential blocks. The tool misreads one block as smaller and of simpler construction than it is. Years later the block suffers a serious fire. The insurer finds it was significantly underinsured and reduces the settlement. The freeholder and leaseholders face a shortfall and claim against the firm that produced the RCA.

How PI usually responds

An RCA claim alleging a negligently low figure is usually handled as professional negligence under the full civil liability cover of the RICS Approved Minimum Wording, subject to the policy terms. These claims can arrive long after the work was done, so the policy in force when the claim is made is the one that responds. Firms that stop trading need run-off; the RICS PII Requirements include run-off arrangements for consumer claims.

Questions of reliance are often central: who commissioned the RCA, who was entitled to rely on it and what the terms said about its limits. Insurers may also look at whether the client was told the RCA was desktop or AI based.

Practical controls

Practical controls include:

Say clearly in the report whether the RCA is inspected, desktop or AI-generated, and what that means for accuracy.
Check floor areas against plans or measured surveys for a sample of properties, and all high-value ones.
Flag non-standard, listed or complex buildings for a full assessment.
Recommend a review date and state the cost data date.
Limit reliance to named parties in the terms of engagement.
Record the named surveyor's sign-off and sampling results.

How Apex helps

Apex arranges PI for quantity surveyors who carry out RCAs, including portfolio work for managing agents. A broker can check that RCAs are declared and that your limit reflects the long tail of this work. See also AI whole-life costing, does QS PI cover AI cost errors?, the QS PI guide and the QS AI hub.

Sources

Frequently asked

Is a desktop RCA acceptable under the RICS AI standard?

The standard does not ban it. If AI is used and has a material impact, the firm needs written supplier due diligence, a named surveyor's reliability decision and dip sampling of automated outputs, and must tell the client in advance that AI is used.

Who can claim if an RCA is too low?

Usually the client who commissioned it, and possibly others the surveyor knew would rely on it, such as freeholders or leaseholders, depending on the terms and the circumstances. Limiting reliance in the terms of engagement helps define who can claim.

Why do RCA claims arrive so late?

The error only matters when there is a serious loss and the insurer compares the sum insured with the true rebuilding cost. That may be years after the assessment, which is why run-off cover and keeping records of how each RCA was produced matter.

Can a managing agent rely on a portfolio of AI-generated RCAs?

A managing agent can use them, but the reports should say how they were produced and what their limits are. The surveyor should flag buildings that need a full inspection, such as listed, complex or high-value properties, rather than letting an automated figure stand.

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.