Subsidence Risk by Postcode: Why Every Homeowner Should Check

In short: Subsidence happens when the ground under a building moves, often because clay soils shrink in dry weather or tree roots draw out moisture. Much of London sits on London Clay, so subsidence is more common here than in many parts of the UK. Postcode risk tools from geological surveys and insurers can show general risk, but they don't replace a survey of the actual property. Warning signs include diagonal cracks near doors and windows and doors that start to stick. Past subsidence affects insurance and mortgages, so check before you buy.