London homes suffer severe cracking as heatwaves trigger record subsidence claims

A series of five heatwaves has dried out the clay layers that support many London properties, leading to widespread subsidence and a spike in insurance claims. Data from the Association of British Insurers show a quarterly record, with households receiving an average of £20,000 in payouts, a 15% rise from the comparable period in 2025. Homeowners are posting images of extensive cracking and shifting doors, describing the experience as frightening.

Experts such as the chief executive of Geobear say the phenomenon is becoming the new norm and may increase over the next 20 to 30 years. The most vulnerable areas include Westminster and Kensington and Chelsea, where older Victorian and Edwardian houses sit directly on the upper clay layers. Traditional repairs like underpinning can cost from £20,000 to over £100,000, adding pressure on insurers and property owners alike.