Survey finding
Wet rot on your survey: what it means and what to do next
Wet rot is one of the most common timber-decay findings on UK surveys, and the most often misdiagnosed. This page sets out what wet rot is, how it differs from dry rot, what fixing it costs, and how mortgage lenders treat it.
Last updated: 6 May 2026. Editorially reviewed: 20 May 2026.
Finding
Wet rot
What this usually means
Wet rot (most often Coniophora puteana, the cellar fungus) is the most common form of fungal timber decay in UK houses. It thrives where timber has been wetted by a leak, condensation, or rising damp and stays damp continuously. Affected timber turns dark, splits along the grain (cuboidal cracking), and crumbles when probed. Unlike dry rot, wet rot does not spread through dry masonry, fix the moisture source and the rot stops.
Why it matters
Wet rot is treatable. The headline buyer concern is finding the moisture source and assessing how much structural timber has been compromised. Mortgage lenders generally treat localised wet rot as standard; widespread wet rot affecting structural members may trigger a retention.
Ask your surveyor
- Check:Can you identify the moisture source, leak, condensation, rising damp, blocked airbrick?
- Check:Is the rot localised or has it affected structural timbers?
Ask the seller
- Check:When was the affected area last inspected, and have any repairs been carried out?
- Check:Have you experienced any leaks or moisture problems in this part of the property?
Next steps
- •Get two written quotes from local trades before negotiating with the seller.
- •Speak to your mortgage broker before exchanging if the finding affects mortgageability.
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What you need to know
Severity
Significant. Specialist follow-up usually warranted before exchange.
Typical cost to fix
Localised wet rot repair (door frame, window cill, isolated joist end): £400–£2,000 including making good. Multiple joist ends or sub-floor timbers: £2,500–£8,000+. A timber and damp specialist's survey runs £150–£400 and is widely worthwhile before any chemical treatment is paid for.
Mortgage impact
Most mainstream UK lenders accept wet rot as a standard finding subject to remediation. Where the rot affects structural timbers (joist ends, lintel timbers, floor plates). The lender may require completed works before drawdown or impose a retention.
Insurance impact
Wet rot is not generally an insurance issue except as a consequence of an insured event (escape of water, storm damage). Pre-existing wet rot is the buyer's responsibility unless the seller's home insurance has accepted a claim.
When to pull out
Pull out only if multiple structural members are affected, the moisture source is fundamental (e.g. lack of damp-proof course, rising damp throughout). The cost approaches 5%+ of purchase price, and the seller refuses to engage.
When to renegotiate, and by how much
Get a written specialist quote covering moisture-source remediation plus timber replacement and treatment. Negotiate on quote plus 15% buffer. Typical settled outcome is the full quote deducted from price, with the seller funding any larger structural element.
Thinking of pulling out or renegotiating? What to do after a bad survey
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Flood, subsidence, EPC, crime, schools, transport, broadband, tenure, age, listed status and price checks where data is available.
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Dry rot (Serpula lacrymans) , often sits near wet rot on a survey and is the next thing to check.
How MyPropertyScan produces this guide, and what it is not
Published by MyPropertyScan and written by Ziad Nasr, who is accountable for its accuracy. No page here is written or reviewed by a chartered surveyor, conveyancer or regulated adviser, and we do not claim otherwise.
This page is not:
- Chartered surveying — we do not inspect properties or produce RICS Home Survey reports
- Legal advice — we do not act as conveyancers or advise on title, tenure or contracts
- Mortgage or insurance advice — we are not regulated by the FCA and give no recommendations
Figures and process steps come from the published UK datasets and standards listed on this page, not from professional practice. Pages are updated when source coverage, survey cost assumptions, or lender and legal requirements materially change. Dataset limitations are set out on the methodology page.
Spotted something out of date or wrong? Email hello@mypropertyscan.com and we will correct it and change the update date.
Sources used
We use UK public and specialist sources where they are available. Public datasets can be incomplete, delayed, or missing for some addresses. Treat them as a starting point, not as a replacement for professional advice.
Source standard: preference goes to official government datasets, statutory bodies, professional standards, and primary dataset publishers. We cite the source family on the page and explain coverage limits rather than filling gaps with unsupported estimates.
- Professional standard: RICS Home Survey StandardRICS standard for condition-based residential surveys in the UK.
- Learn more from: RICS consumer guide to surveysConsumer-facing guide to survey types and when each level is appropriate.
- Official guidance: GOV.UK buying or selling your homeGovernment overview of the home buying and selling process.