The UK's largest insurer has been hit by a rise in subsidence claims after an extremely hot summer left households across the country dealing with property damage caused by shifting ground. Aviva said it experienced a jump in claims between July and September, with claims continuing into October, according to chief executive Amanda Blanc. The company did not provide details on the scale of the increase, but the announcement follows reports from rival insurers showing the extent of the problem across the industry.
Hastings Direct said it received record subsidence claims in August, up 140% compared with a year earlier. Axa, one of the UK's biggest home insurers, has described the period as a surge year for subsidence. The value of claims has also hit a record high. The average subsidence claim in the UK reached £20,000 between April and June, more than £2,000 higher than a year earlier, according to the Association of British Insurers. Insurers paid out £72m for domestic subsidence claims in that period, compared with £60m in the same period a year before.
The underlying cause is straightforward: drier summers cause the ground under houses to shrink, which undermines a property's foundations. The ground then expands in wetter winters, which can further damage homes. August this year was the joint hottest month ever recorded around the world, following another record hot summer in the previous year. Older properties with shallow foundations and those built on clay-rich soil are facing the biggest threat, with areas including London, Essex, Kent and areas around Oxford among the most vulnerable.
The British Geological Survey estimates that up to 11% of UK homes, more than 4.2m houses, could be at risk of subsidence by 2070 because of the worsening climate crisis. Blanc advised homeowners could reduce the risk by keeping a close eye on drains, pipes and gutters, and fixing any leaks that could affect the ground under homes. She said managing trees and plumbing were key priorities for homeowners seeking to prevent damage.
Despite the rise in subsidence claims, Aviva reported strong financial performance. General insurance premiums rose 19% to £11.8bn in the third quarter. Blanc said the company was in good shape, noting that performance had been excellent in the first nine months of 2026, demonstrating benefits of scale across its diversified business and continuing to deliver strong, profitable growth, particularly in capital-light areas of general insurance and wealth.
For UK homeowners and those seeking insurance, the surge in claims means repair bills are climbing sharply while the long-term risk of subsidence damage is expected to grow significantly over the next four decades.