Record heat cracks London homes as Britain faces surge in subsidence claims

London homes are developing cracks as five consecutive heatwaves have dried out the soil, creating a historic risk of land subsidence. According to data from the Association of British Insurers, insurance claims related to subsidence have recently reached a record high. Affected families are receiving an average of £20,000, which is 15 percent higher than during the same period in 2025. London residents on Reddit have described experiences of “terrible cracks” and doors becoming stuck.

One homeowner said it was genuinely frightening when the shifting foundations caused the kitchen to move as well. Geobear Chief Executive Mr. Otso Lahtinen said, “What is happening now is incredible. This is the new normal, and it seems likely to happen more frequently over the next 20 to 30 years.” According to Aviva, Westminster and Kensington and Chelsea are among London’s most vulnerable areas.

London’s clay swells when wet and contracts when it dries. Climate change is intensifying these fluctuations. By 2025, insurance payouts for subsidence-related damage in the UK had risen by nearly 90 percent over four years to £297 million, a record. Homes built during the Victorian and Edwardian eras, with foundations resting on London’s upper clay layers, are particularly vulnerable. In contrast, modern office buildings in the City of London and Canary Wharf generally have deeper foundations. Subsidence is one of the growing heat-related problems facing Britain. Meanwhile, extreme heat has forced schools to close, bus drivers have gone on strike and banks have relaxed office attendance requirements. At the same time, England is facing drought, while hospitals are struggling to cope with additional pressure.

London Mayor Mr. Sadiq Khan has warned that private investment may be needed to finance measures to help London adapt to climate change. According to his office, spending could reach as much as £36 billion a year through the 2050s. Data from the Federation of Master Builders shows that property values in Britain can fall by 20 to 25 percent because of subsidence, while the cost of strengthening building foundations can range from £20,000 to more than £100,000.

Deloitte partner Ms. Cherie Chan said subsidence is a major challenge for Britain’s home insurance sector and an increasingly important risk caused by climate change. She warned that extreme weather in 2026 could generate further insurance claims and worsen the situation surrounding outstanding claims from 2025. According to estimates by the British Geological Survey, under a medium-emissions reduction scenario, 1.8 million properties, or 5 percent of the UK’s total, could be at risk of subsidence caused by soil contraction and expansion by 2070.

Under higher emissions, the figure could rise to 4.2 million properties, or 11 percent. London, Kent and southeast England will face the greatest risk. Geobear said homeowners’ inquiries have reached a record high this summer. One insurance company reported receiving 180 claims in a single day.