Check subsidence and the ground before you buy
Shrinking clay is the most common cause of subsidence in Britain: clay soils dry out and shrink in hot summers, and swell again when it rains. The British Geological Survey maps where the ground is prone to moving.
Free to start with a postcode. No account needed. See an example report.
How to check a property for subsidence risk
Check the ground
The full report shows ground movement hazards for the area around the house from the British Geological Survey: shrink-swell clay, landslides, compressible and collapsible ground, sinkholes and running sand, plus non-coal mining.
Look ahead
Hotter, drier summers make clay shrink more. The full report shows how clay shrink-swell around the house is expected to change by the 2030s and 2070s.
Check for coal mining separately
Our report doesn’t cover coal mining. In a former coalfield, your solicitor can order a mining report from the Mining Remediation Authority, formerly the Coal Authority.
Get the house surveyed
A ground hazard nearby isn’t evidence the house has moved. A surveyor looks for the signs, such as cracks around doors and windows, and can tell you whether to investigate further.
Ask the seller
Ask about past subsidence, insurance claims and underpinning. These affect insurance and are hard to spot at a viewing.
What we check
- Ground movement hazards around the houseFull report
- Non-coal miningFull report
- How a changing climate affects the clay, by the 2030s and 2070sFull report
Coverage: England, Scotland and Wales. Coal mining isn’t included.
Sources: British Geological Survey GeoSure hex grids; British Geological Survey GeoClimate (UKCP18). All data sources
Why ground conditions matter when you buy
Subsidence can be expensive to put right and can make a home harder to insure. A past claim stays on the record and usually has to be declared.
Clay is common under many towns and most homes on it never have a problem. Knowing the ground helps you decide which survey to get and what to ask your surveyor to look at.
Questions to ask the seller, your solicitor or surveyor
- Has the house had subsidence, or an insurance claim for it?
- Has it been underpinned, and is there a certificate of structural adequacy?
- Are there large trees close to the house, and whose are they?
- Is the area a former coalfield, and has a mining search been done?
The full report ties questions like these to what it finds at the house.
Common questions
What causes subsidence?
Most often, clay soils shrinking in dry weather, which trees can make worse by drawing water from the ground. Leaking drains, old mine workings and natural cavities can also cause it.
Does a clay area mean the house will subside?
No. It means the ground can move, so it’s worth looking for signs and asking about the house’s history. A surveyor can tell you more about the house itself.
Does the report cover coal mining?
No. It covers non-coal mining, such as old tin, lead, chalk or salt workings. For coal, ask your solicitor for a mining search from the Mining Remediation Authority.
Official records, not advice. We never score properties or tell you whether to buy. Check a postcode