Costs guide
How Much Does a Damp Survey Cost?
Updated 23 July 2026
An independent damp and timber survey costs around £150 to £400 in 2026, depending on the size of the property. Treatment companies often offer free damp surveys, but they earn their money from the remedial work they recommend, so an independent surveyor's report is worth paying for. If treatment is needed, damp-proofing typically costs £2,000 to £6,000 for a terraced or semi-detached house.
Damp survey and treatment costs (UK, 2026)
| Item | Typical cost | Notes |
|---|---|---|
| Independent damp & timber survey | £150 to £400 | By a PCA-qualified or independent surveyor |
| Free contractor survey | £0 | Conflict of interest: they sell the treatment |
| Damp-proof course injection | £1,500 to £4,000 | Per affected elevation, incl. replastering |
| Condensation / ventilation fixes | £300 to £1,500 | Extractor fans, PIV units |
| Timber treatment (rot, woodworm) | £500 to £2,500 | Often quoted alongside damp work |
When buyers actually need a damp survey
The usual trigger is a mortgage valuation or RICS survey that notes "high moisture readings" or "damp staining" and recommends a specialist damp and timber report. Lenders sometimes make a retention, holding back part of the loan, until that report is produced.
Book one whenever a survey flags damp, you can see tide marks, peeling paper or smell mustiness on viewing, or the property is pre-1930 with solid walls, where damp diagnosis is genuinely harder.
Independent vs free surveys: the conflict of interest
A free survey from a damp-proofing contractor is a sales visit. The surveyor is often paid partly on the work they specify, and the industry has a long record of prescribing chemical damp-proof courses for what is actually condensation or a leaking gutter, problems that cost a few hundred pounds, not several thousand.
An independent damp surveyor charges £150 to £400 and has nothing to sell beyond the report. For a purchase decision, and especially for renegotiating the price, an independent report carries far more weight with sellers and lenders alike.
Using the report in your negotiation
- Get itemised treatment costs in the report, then negotiate the purchase price down by that figure rather than asking the seller to arrange works.
- Distinguish rising damp (rare, expensive) from condensation and penetrating damp (common, usually cheap to fix): the diagnosis drives the money.
- If the lender has made a retention, the report plus quotes is what releases it.
- In a period property, expect some moisture readings; the question is whether there is active water ingress, not whether an old wall reads damp.
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Frequently asked questions
How much is a damp survey in the UK?
An independent damp and timber survey costs roughly £150 to £400 in 2026 depending on property size and location. Contractor surveys are often free, but the firm earns from the treatment it recommends, so independent reports are considered more reliable for purchase decisions.
Is a free damp survey worth it?
As a quick screen, possibly; as the basis for a purchase decision, no. Free surveys are provided by companies selling damp-proofing work, and over-specification is well documented. Pay for an independent report if money is riding on the answer.
How much does damp-proofing a house cost?
A chemical damp-proof course with replastering typically costs £1,500 to £4,000 per affected wall run in 2026, while fixing condensation with ventilation improvements is often £300 to £1,500. Whole-house tanking or major works in older properties can run well beyond that.
Should I pull out of a purchase because of damp?
Usually not without numbers. Most damp is fixable at a known cost, which makes it a negotiation item rather than a deal-breaker. Get the independent survey, price the works, and renegotiate; walk away only if the cause is structural or the seller will not move on price.
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