Survey finding
Floor joist decay: what to do
Joist end decay is common in solid-wall property. This page covers diagnosis and costs.
Last updated: 6 May 2026. Editorially reviewed: 20 May 2026.
Finding
Floor joist decay
What this usually means
Joist ends embedded in damp masonry decay over time, especially in solid-wall property without DPC. The fix is sister-joisting or hanger replacement plus addressing the moisture source.
Why it matters
Floors become unsafe in extreme cases. Surveyors typically pick this up from springiness or visible damp at skirting.
Ask your surveyor
- Check:How extensive is the decay?
- Check:What is the moisture source?
Ask the seller
- Check:Has any flooring work been done?
- Check:Are floorboards routinely lifted?
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
Investigation £200-£500. Sister-joisting one joist £400-£900. Whole room re-joist £3,500-£8,000.
Mortgage impact
Standard unless extensive.
Insurance impact
Standard.
When to pull out
Not on its own.
When to renegotiate, and by how much
Quoted works plus 15% buffer; typical £1,500-£6,000.
Thinking of pulling out or renegotiating? What to do after a bad survey
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Run a free previewHow 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Spotted something out of date or wrong?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.