UK homes could collapse or sink in heatwave as map shows areas most at risk

UK homes could collapse or sink in heatwave as map shows areas most at risk People living in certain parts of the country are more at risk than others of the issue that can worsen in the heat This week’s heatwave could cost UK homeowners thousands of pounds, with the Met Office issuing a red warning for parts of the country as temperatures could reach 40C. A new map shows if your property is at risk, as subsidence can be caused by heatwaves and prolonged dry spells. A subsidence risk map has been created to help homeowners identify the worst-affected areas. It comes as subsidence has overtaken every other claim type to become the single biggest payout in UK home insurance, according to new research by Uswitch home insurance experts. A statement on the Uswitch website explains: "We mapped subsidence risk across Britain. The good news: most of it is fine. The unfortunate news: there is a thick band of land (from Dorset up through London, the East and into North Yorkshire) that sits on soil that shrinks when it's dry and swells when it's wet. That's subsidence. It's one of the most expensive claims you can make on your home insurance." The Association of British Insurers reported a record £307 million paid out on subsidence claims in 2025, with the average claim reaching close to £17,000. This is more than the average payout on any other home insurance claim type, including theft, fire or flood. The catch is in the excess. Where most policies charge £100 to £250 when a homeowner makes a routine claim, the excess on subsidence cover typically sits between £1,000 and £2,500 - around four to ten times higher. The gap exists because subsidence claims are structural and expensive to investigate, but it means homeowners face four-figure costs before their insurer starts paying. The risk is not evenly spread. One in 10 of the land zones in Britain sits on soil classed as a significant subsidence risk by the British Geological Survey, with the worst-affected band running from Dorset up through London and the East into North Yorkshire. London Clay, the soil that sits beneath much of the capital and the Home Counties, is the highest-risk geology in the country. If you suspect subsidence, it is worth getting a chartered surveyor’s diagnosis before contacting your insurer. Doing so prevents the enquiry from being logged in the Claims and Underwriting Exchange (CUE) database, which can affect future premiums even if the crack turns out to be harmless. Leoni Moninska, Insurance Expert at Uswitch has shared tips on what homeowners can do if they suspect subsidence damage. She said: "Subsidence is an area where homeowners can easily be caught out - both by the risk to their property and by the excess they’d face on a claim. "If you spot a crack, photograph it and monitor it over a few months. If it’s still changing, call a chartered surveyor for a diagnosis before involving your insurer. "Use our subsidence risk map to check your area. If needed, make sure your home insurance policy includes subsidence cover, and find out what excess you’d face - so you know you’re on the right policy for your home." Uswitch says if you're in 'Moderate' or 'Significant' ground, it's worth checking if your home insurance covers subsidence. Most policies do, but the excess (the bit you pay before the insurer covers the rest) is usually higher than for other claims.