Insights
Contractor overclaim: ten warning signs to spot before you pay
A monthly valuation is the contractor's invoice. These are the patterns an independent monitoring surveyor checks for before signing it off.
Key facts
- On unmonitored projects, contractor valuations typically overstate by 5–15%.
- Front-loaded prelims are the single most common overclaim pattern.
- Materials on site count toward valuation only if properly stored, labelled and insured.
- Variations claimed in valuation must be instructed in writing, claims without instructions should be rejected.
- Retention (usually 5%) is held until the defects period ends, typically 6–12 months after practical completion.
A monthly valuation is the contractor's invoice. It is also the highest-leverage point of cost control on the entire project, because what is certified is what is paid.
The contractor's job is to claim. The monitoring surveyor's job is to certify what is actually in place.
The ten patterns
- Front-loaded preliminaries. Prelims claimed faster than programme completion. Honest practice is straight-line.
- Materials not on site. Materials claimed but not delivered, or delivered but not properly stored, identified or insured.
- Trade completion overclaimed. "First fix electrics 100% complete" when half the second-floor outlets are still missing.
- Variations claimed without instruction. Variation values added to the gross valuation before a written instruction exists.
- Provisional sums released without justification. A provisional sum drawn down without invoices or subcontract orders to support it.
- Off-site fabrication without vesting certificates. Joinery, steelwork or M&E modules claimed off-site without proper paperwork transferring ownership.
- Retention release attempted early. The 2.5% half-retention release should follow practical completion certification; the second half follows the defects period.
- Damaged or remedial work claimed at full value. Work that needs to be done again should not be paid for twice.
- Specialist subcontract work claimed before subcontract sign-off. Owner pays main contractor, who pays subcontractor, the subcontractor's progress should be evidenced.
- Loss-and-expense claims bundled into valuation. Loss and expense is a separate contractual process, not a line item slipped into the monthly bill.
What an independent monitoring inspection looks like
A monitoring surveyor visit takes two to four hours on most projects. The output is:
- A measured assessment of work in place versus the contractor's claim.
- A photo record of materials on site and trade progress.
- A list of items reduced or rejected with reasoning.
- A recommended certified value to the build cost overseer.
The certified value goes onto the interim certificate. Payment follows certification. The contractor has a right to challenge, through the contract dispute process, not by withholding work.
Cost of monitoring versus cost of overclaim
On a £1m project with monthly valuations, a monitoring surveyor typically costs £8,000–£15,000 across the life of the contract. Average overclaim recovery on a previously-unmonitored project: £40,000–£120,000. The economics are not subtle.
Frequently asked
- Who certifies a contractor's valuation?
- Under your build contract contracts, the build cost overseer issues the interim certificate. The certified amount may differ from the contractor's claim. Under more complex projects, an independent cost expert or monitoring surveyor inspects and measures first, then advises the build cost overseer.
- What happens if the contractor over-claims?
- The certifier reduces the certified amount to reflect actual work in place. The contractor is paid the certified amount, not the claimed amount. Repeated overclaiming is a contractual issue and should be raised formally.
- What counts as 'materials on site' in a valuation?
- Materials that are: delivered to site, properly stored and protected, clearly identified to the project, covered by the contractor's insurance, and not at risk of removal. Off-site materials are valued only with strict conditions and supplier vesting certificates.
- Why are prelims often over-claimed?
- Prelims are a lump sum the contractor recovers across the project programme. The fair approach is straight-line over the programme. Many contractors front-load prelims to improve cashflow, claiming 50% by month three on a six-month job. A monitoring surveyor checks the prelims claim against programme completion.
- When should I appoint a monitoring surveyor?
- On any project above £500,000 with monthly valuations, or any project funded by a lender. The fee is typically 0.25%–0.75% of construction value and almost always saves multiples through accurate certification and variation control.
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