Survey finding
Category 4 or 5 structural cracks: should you walk away?
Category 4-5 is the territory where lenders and insurers usually step back. This page sets out what the classifications mean and the realistic options for buyers.
Last updated: 6 May 2026. Editorially reviewed: 20 May 2026.
Finding
Structural crack BRE category 4-5
What this usually means
BRE category 4 means cracks 15-25mm with extensive damage, walls leaning or bulging, and structural instability. Category 5 (>25mm) is severe enough that the building may be unsafe and sections may need rebuilding. Both indicate failure of the primary structure rather than finishes.
Why it matters
At categories 4-5, structural engineers and lenders treat the property as a project rather than a home. Mortgage offers are commonly refused or made conditional on completed works.
Ask your surveyor
- Check:What is your assessment of the cause and whether the movement is active?
- Check:Do you recommend immediate structural engineering involvement before any further commitment?
Ask the seller
- Check:What works are planned or already commissioned to address the damage?
- Check:Are insurance arrangements transferable, or would I need specialist cover?
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.
Tool shortcut
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What you need to know
Severity
Deal-breaker territory. Most buyers walk away unless seller funds remediation in full.
Typical cost to fix
Structural engineering reports plus monitoring £700-£2,000. Stabilisation and rebuilding works typically start at £40,000 and can exceed £150,000 for category 5 damage; underpinning combined with rebuilding is the normal package.
Mortgage impact
Most mainstream lenders refuse outright at category 4-5 unless works are complete. Specialist lenders may consider it but at materially higher rates.
Insurance impact
Standard buildings insurance is rarely available; specialist subsidence insurers will quote, often with high excesses (£1,000-£2,500) and a long monitoring period before standard cover resumes.
When to pull out
Walk away unless the seller is funding all stabilisation works to completion before exchange, with insurer-backed warranty. The risk premium on category 4-5 rarely makes sense for a buyer financing in the standard way.
When to renegotiate, and by how much
If proceeding, expect 15-30% off the agreed price plus seller-funded works. Most buyers do not proceed.
Thinking of pulling out or renegotiating? What to do after a bad survey
Run the check on this address
The Survey Decoder explains the wording. The full report adds address-specific flood, subsidence, EPC, crime, listed status, building age and price comparison data, so a single finding isn't judged in isolation.
Run the check
Check subsidence signals for a UK address in 15 seconds
Directional BGS 1:1 million engineering geology, building age, tree context and the things to ask your surveyor.
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.