Beware of that sinking feeling

Look out for telltale cracks

Summer might be over, but its effects could last much longer than you think.

The record-breaking hot weather is expected to lead to a big increase in cases of subsidence.

Some estimates say the number of insurance claims for damage to properties could double to 50,000 over the next year.

The big problem has been the lack of rain. Dry weather causes the ground to shrink and crack. And if the winter months are dry, problems could get even worse.

In the UK, it's the south rather than the north which is most at risk.

This is because much of London and the south-east is clay, which is more seriously affected.

Normal level

A constant period of rain is needed to rehydrate the earth. Where homes are built near trees, which soak up moisture, the water might need to seep down up to four metres to swell the clay back to its normal level.

But structural engineer Brian Clancy thinks it's too late for some people - the damage will already be done.

The ground is baked hard in some places

"By now the ground will be baked hard, so the vast majority of rain which falls now will just run off," he says.

The average cost of repairing subsidence damage is about £10,000, and sometimes policyholders are asked to meet the first £1,000 of a claim.

A large number of claims could see insurance premiums rise in the future.

However, the Association of British Insurers says that's unlikely as the cost of subsidence related claims is already factored in.

The last really dry year was 1995, when the drought resulted in a 60% increase in claims for subsidence.

And in 1976, when the UK had its hottest summer, the huge number of claims nearly crippled the insurance industry.

The industry is gearing up for a winter of subsidence claims. We're seeing a 20 - 30% rise in claim notification. David Mansfield, Loss adjuster

Some insurers report that claims have already gone up this year, but the full extent won't be known for some months.

"Over the last two to three months it has escalated considerably, particularly in the London area," says David Mansfield of loss adjusters Davies & Co.

"At the moment we're seeing what is the beginning of possibly a much larger inrush of claims."

So what are the telltale signs of subsidence?

Cracking round doorframes

Doors and windows sticking

New cracks in walls more than 3mm wide

Conservatory or extension coming away from house

Solid concrete floors becoming uneven.

David Mansfield says about half of claims result in cosmetic repairs and the damage being monitored for further movement. Occasionally an offending tree will be removed.

However, at the other end of the scale, serious subsidence could require underpinning, with the house being vacated for several months.

"People have a lot of money tied up in their houses and they're bound to be nervous if they get cracks," says David.

"My view is that you shouldn't panic - contact your insurance company at an early stage.

"Subsidence claims are fairly straightforward. Loss adjusters and surveyors are very experienced in dealing with claims."