FOR sun-worshippers, soaring temperatures and sunny skies make it easier to accept the impact of global warming on the British climate. But for homeowners, the legacy of extreme weather could be more damaging than a bit of sunburn.

Households face an increasing risk of damage to their properties caused by subsidence, storm damage and flooding because of climate change, according to the Association of British Insurers (ABI).

Premiums for home insurance are soaring as new weather patterns take their toll. The most recent figures from the ABI show that the number of weather-related insurance claims doubled between 1998 and 2003 compared with the previous five years. The cost of claims has also been rising.

This trend is likely to continue, as the Met Office predicts warmer than average temperatures in the UK over the next three months.

Malcolm Tarling, of the ABI, says: “Insurers are not climatologists. They do not base their premiums on predictions of future risk from climate change; they consider historical patterns, and what is happening now.”

Churchill, the insurer, estimates that half of all UK properties will sustain damage at least once because of storms.

Force majeure, or acts of God, were traditionally excluded from insurance policies, so insurers would not pay out if a house was damaged by a lightning bolt. Now most buildings insurance policies cover freak weather as standard, but exceptions and excesses still apply, depending on the insurer.

Sarah Baldwin, of confused.com, the insurance price comparison site, says: “Every policy is different. Individual insurers often refuse any cover at all, or rate specific acts of nature differently. If you are worried about unpredictable weather, it is vital to check the general exclusions and conditions.”

Exclusions apply to all home insurance claims, whatever the cause of the damage. Holidaymakers away for more than 30 days should beware; many insurers will not honour claims made if the home has been left unoccupied for more than a month.

There is usually a time limit of about three months in which to make a claim. Excesses will typically set you back by £50, but rise to £250 if the house is unoccupied for more than 24 hours. If you need to fund accommodation while your property is being repaired, most insurers will pay the full sum, but will limit the payout to 20 per cent of the sum assured. The ABI says that unless you are staying in a five-star hotel it is unlikely that your accommodation costs will exceed this amount. But if they do, you will have to fund the rest yourself.

Record temperatures in July have increased the threat of subsidence — the downward movement of ground below a building. There is a higher risk if there are trees close to the house, because they suck up water during hot spells, causing the ground to compress.

The first sign is cracks appearing in walls although, the ABI points out, not all cracks are a sure sign of subsidence. Diagonal cracks thicker than a 10p coin that get wider at the top may indicate ground movement. The excess for claims on subsidence is usually £1,000, but can be as high as £5,000.

Subsidence damage can cost up to £50,000 to repair, if underpinning is needed, but the average cost of a claim is £8,000. You could still be denied a payout, depending on the cause of the subsidence. An insurer may consider damage caused by clogged and damaged drains to be the fault of the homeowner — and refuse it.

Freak flooding can be equally devastating, but households in high-risk areas will find it harder to obtain cover because insurers have access to high-tech geo-mapping techniques to measure flood risk. They will also face high premiums. Most policies cover damage to sheds, outbuildings and garages. But gardens, which includes gates, fences, hedges and plants, are not usually covered on a basic policy, although cover for these can often be arranged separately.

Some insurers differentiate between flood and rising ground water and will not always pay out on the latter. Endsleigh, for instance, refuses claims on damage to outbuildings caused by a rising river level if the main property is not also damaged.

Vehicles damaged by flood water will be covered only by fully comprehensive motor insurance — the most expensive cover for drivers. For a 30-year-old male driving a Ford Fiesta, best-buy fully comprehensive insurance costs £167.62, compared with £116.60 for third-party fire and theft.

The risk of lightning is harder for insurers to predict than flooding , but the effects can be be costly.

Mark Bishop, of Cornhill Direct, the insurer, says: “The number of claims that we receive for lightning damage is surprisingly high, because one bolt can damage many houses at once.”

Most insurers will cover you for damage caused by lightning, including fire, even if it strikes someone else’s property. Conditions are often tighter for general storm damage. Insurers have a definition of what counts as a storm.

Esure and More Than, for instance, define a storm as a violent gale of force 10 on the Beaufort scale, with winds reaching speeds of at least 55mph. Churchill will accept claims from milder storms with wind speeds of force 9.

Some policies will not pay out if a few tiles are swept off the roof by an isolated strong gust of wind, while some exclude damage caused by objects such as trees and electricity pylons that fall on to a house.

For more on insurance visit www.timesonline.co.uk/insure

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