Is the ground under a property at risk of sinkholes or subsidence?
Enter a postcode to see the mapped geology, soil, nearby trees and British Geological Survey records, with a plain-English explanation of what each one means and what to check next.
Live data from the British Geological Survey, the UK Soil Observatory and Forest Research, assessed against NHBC guidance on building near trees.
Five ground factors, each explained
Most UK ground movement comes from a handful of causes. The report looks at each one separately rather than blending them into a single score, so you can see why a result is flagged.
Sinkholes and dissolution
Is the property on chalk, limestone, gypsum or salt, the soluble rocks behind most natural UK sinkholes?
Shrink–swell clay
Clay soils shrink in dry weather and swell when wet. We combine the soil texture and the underlying geology.
Trees near the building
Mapped tree canopies within 50 m, their heights and distances, tested against NHBC zones of influence.
Soft or compressible ground
Peat, alluvium and other soft deposits that can settle unevenly under a building.
Recorded movement and mining
BGS landslide records, borehole logs you can view and historic mine plans near the site.
Then add what you know
Foundation depth, extensions, cracks, leaking drains, recently felled trees and the species of trees in the garden all change the picture. Add them to turn the screening into a list of priority checks.
From postcode to priority checks in a minute
- Enter a postcode. We locate it and query the national datasets live.
- Put the pin on the building. A postcode can cover a whole street. Dragging the pin onto the house makes tree distances and geology specific to it.
- Read the five indicators. Each shows Higher, Moderate or Lower, with the reason.
- Add building details and site trees. The report lists what to investigate first, such as a foundation check, drain survey or mining search.
- Print or download the evidence to share with a surveyor, engineer or insurer.
Subsidence is rising with hotter, drier summers
New BGS projections published in June 2026 estimate that by 2070 about 1.8 million British properties (5%) could be highly or extremely likely to be susceptible to clay shrink–swell under a medium emissions scenario, rising to over 4.2 million under high emissions. In London the share could exceed a quarter of all properties.
Domestic subsidence claims totalled £307 million in 2025, according to figures cited by BGS.
Where the information comes from
British Geological Survey
1:625,000 bedrock and superficial geology, the National Landslide Database, onshore borehole records and the mine plans index, through the BGS OGC API.
UK Soil Observatory
The BGS Soil Parent Material Model: soil texture, subsoil grain size, depth and carbonate content, plus mapped peat.
Forest Research
The Trees Outside Woodland map of England: lone trees, groups and small woods mapped from lidar and aerial imagery, with canopy heights.
Full data sources, scales and limitations
Check a postcode
See the geology, soil, nearby trees and BGS records for any UK postcode, explained.