Updated October 2026 · Fraser Bond
Surveys · Subsidence
Checking subsidence risk
Postcodetools
Claysoils
Surveystill needed
Full guidebelow
In short: Postcode subsidence tools from geological surveys and insurers show the general ground risk for an area, which is often higher on London Clay. They don't tell you about a specific building, so if you see cracks or are buying an older home, get a survey. Our full guide covers warning signs, insurance and mortgages.
Frequently asked questions
Are postcode checkers accurate?
They show general risk, not the condition of a specific property.
When do I need a survey?
Before buying, or if you notice cracking.
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