London buildings face subsidence risk from extreme heat

London and southeast England are experiencing a significant subsidence problem driven by unusually hot and dry weather. As heat waves dry out the city’s clay-based soil, the ground shrinks and shifts, causing buildings to sink and develop structural issues such as wall cracks, warped windows, and stuck doors.

The British Geological Survey describes subsidence as one of the most damaging geohazards in the UK today. The phenomenon is caused by a ‘shrink-swell’ process where clay soil expands when wet and contracts during dry periods. This risk is exacerbated by tree roots that seek moisture from the soil beneath homes, further drying it out.

Older properties are particularly vulnerable due to shallower foundations, and more than half of London’s homes were built before 1945. Projections suggest that in some parts of the city, 100% of properties could face possible or probable subsidence risk by 2030.