What a Damp Survey Costs in London
What you pay, what you get for it, and why a free survey is rarely free.
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Damp Reports for
Lenders & Solicitors
A valuation says "damp — refer to a specialist", a retention appears on the mortgage offer, and the chain stalls. What that actually requires is narrower and more fixable than it sounds.
Last reviewed September 2026 by Tony Murphy, Founder & Managing Director. We update these guides in place rather than letting them go stale.
The Short Answer
- A valuer's damp referral is professional caution, not a diagnosis.
- What lenders want is a specialist damp and timber report with a costed specification.
- Cost is £295–£450; turnaround is usually under a week.
- A retention is released on either completed works with a guarantee, or a report showing none are needed.
- Keep the guarantee assignable — the next buyer's solicitor will ask for it.
Why Did the Valuer Flag Damp?
A mortgage valuation is a short inspection carried out for the lender, not for you, to confirm the property is adequate security. The valuer typically runs a conductivity meter along ground-floor walls and notes anything elevated.
They are not damp specialists and are not attempting a diagnosis. Their professional indemnity position requires flagging anything that might represent a defect, so the referral wording appears readily — including on walls that are dry but salt-contaminated from a problem resolved decades ago. See why surface meters mislead.
The consequence is a retention: the lender withholds part of the advance until the matter is resolved.
What Does a Lender Actually Want?
Almost always one of two things. Either a specialist report concluding no remedial work is required, with reasoning; or a specialist report with an itemised specification and fixed price, plus evidence the work has been done and is guaranteed.
What lenders do not generally accept is a contractor's quotation on its own. A price is not a diagnosis, and a quote from a firm that also wants the work carries an obvious incentive problem.
What to ask your solicitor
Ask for the exact wording of the retention condition before commissioning anything. "A report from a suitably qualified damp and timber specialist" and "evidence of completed works with an insurance-backed guarantee" are different requirements with different costs and timescales.
What Is in a Damp and Timber Report?
It is a formal document written to be read by a lender, solicitor or surveyor rather than by a homeowner. Ours contains:
- Property details, date of inspection and the qualifications of the inspecting surveyor
- External inspection findings — ground levels, drainage, rainwater goods, pointing, render, airbricks
- Internal findings room by room, with photographs
- Moisture profiling results and, where taken, salts analysis of drilled masonry samples
- Inspection of accessible structural and joinery timber for rot and insect attack
- A clear statement of cause, and the reasoning that excludes the alternatives
- An itemised specification with a fixed price, or an explicit statement that no remedial work is required
- Guarantee terms that would apply
That last point matters more than it looks. A report that says "no works required, and here is why" is often exactly what releases a retention — and we write plenty of them.
How Long Does It Take?
Surveys are normally booked within two to five working days across London, with the written report inside 48 hours of the visit. Where an exchange deadline is running, tell us and we will prioritise.
Where works are required, allow two to five days on site for typical residential damp proofing, plus drying time before decoration — though lenders generally release retentions on completion of the works and issue of the guarantee, not on completion of decoration.
| Stage | Typical timescale |
|---|---|
| Survey booked | 2–5 working days |
| Written report issued | Within 48 hours of the visit |
| Remedial works (if required) | 2–5 days on site |
| Guarantee documentation issued | On completion |
Who Should Pay — Buyer or Vendor?
Usually the buyer commissions it, because the buyer needs a report they can rely on and the lender's retention is on the buyer's advance. It also avoids the awkwardness of relying on a report obtained by the party with an interest in the outcome.
The cost is frequently recovered in the negotiation that follows. If the report identifies £3,000 of works, that is a documented, itemised figure to put to the vendor — considerably stronger than a general concern about damp. Our guide on buying a house with damp covers the negotiation in more detail.
Keep the Paperwork
When works are carried out, you should receive the survey report, the specification, the invoice and the guarantee document. Keep them together.
When you come to sell, the buyer's solicitor will ask for exactly this bundle, and having it to hand removes one of the more common conveyancing delays. Check the guarantee is assignable to a future owner — ours are.
Questions
Lender ReportsFAQs
It means the valuer recorded elevated moisture readings and, as professional caution, referred the matter on. It is not a diagnosis and does not confirm a defect exists. The practical consequence is usually a retention on the mortgage advance until a specialist report resolves the question — which may well conclude that no remedial work is needed.
A formal specialist report covering moisture investigation and inspection of accessible structural and joinery timber for rot and insect attack. It states the cause, the reasoning, and either an itemised costed specification or an explicit statement that no works are required. It is the document lenders and solicitors normally ask for, and costs £295 to £450 in London.
Either by providing a specialist report concluding no works are required, with the reasoning set out, or by having the specified works completed and supplying the invoice and guarantee. Check the exact wording of the retention condition with your solicitor first, because what is required varies between lenders and determines both cost and timescale.
Usually not on its own. Lenders generally want a report from a qualified specialist that establishes cause and extent, not simply a price for a treatment. A quotation from a firm that also stands to carry out the work does not address the question the lender is asking, which is whether the property is adequate security.
Ours are assignable to a new owner. You receive the guarantee documentation on completion along with the report and specification — keep all three together, because a buyer's solicitor will routinely ask for them and producing them promptly removes a common source of delay.
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Next Step
Get the Cause Found & Fixed
Book a survey and you get a written report: what is causing the damp, what it takes to fix it and what it costs. No pressure, no guesswork.
Survey fee deducted from the cost of works if you proceed