May 19, 2006 12:15 pm

House subsidence

It is the sight every homeowner dreads – cracks appearing in the walls of their home. And as everyone is predicting a long hot summer, insurers are forecasting record subsidence levels in the autumn as temperatures start to cool down again and people’s walls start to crack. Problems with subsidence can mean higher insurance premiums, being refused buildings insurance cover and ultimately having trouble selling your home.

So what exactly is it?
Subsidence appears when the foundations of a house start to sink. It is different to heave; which is the upward movement of the ground supporting the building, and landslip; the slow slide of the ground/your house down a slope.

What causes it?
It can be as simple as the type of soil that your house is built on. Clay soils are particularly vulnerable as they shrink and swell according to their moisture content.

What about trees? Can they cause subsidence?
John Parvin, chairman of the Subsidence forum and claims manager at Zurich, says trees and shrubs are also to blame as they can suck the moisture from clay soil and cause it to shrink. This is especially likely during long periods of dry weather as parched plants push their roots under and through foundations in search of water. But Parvin says it is not always advisable simply to chop down trees because the clay could swell and destabilise your home’s foundations anyway. It’s better to prune trees and shrubs to a sensible height.

How can I tell which tree is to blame for damage to the foundations?
Halifax Home insurance engages DNA profilers to identify trees causing subsidence. The offending tree can then be managed, by removal or pruning, reducing repair costs and damage.

Is there any way to avoid my house sinking into the ground?
Although some areas are very prone to subsidence, there are things you can do to avoid it. Basic maintenance is important – drains, pipes and gutters should be checked regularly to ensure there are no blockages, splits or leaks.

Should I panic if cracks appear?
Don’t worry when cracking first appears – it is probably only superficial. Note the size and direction of cracking and monitor whether it worsens. It may be helpful to take photographs for comparison. If cracks widen and spread rapidly, contact your insurer to start the claims process. The insurer will send an expert to examine the problem and advise on appropriate action.

How much might it cost me?
The first thing to do is check your insurance policy. Your buildings insurance should cover subsidence, though the extent of the cover will vary. Most policies have a £1,000 excess while the average claim paid out is £4,000. Some policies also cover you for alternative accommodation while repairs are made. However damage to garden walls, swimming pools, gates, fences and driveways may be excluded.

Will I have to pay more for my insurance?
If your home is an area prone to subsidence, the increased level of risk means that your premiums or excesses will be higher. However, even if your property has been affected by subsidence you should still be able to insure it as long as repair work has been carried out successfully and you can show that you have taken a number of steps to minimise the risks.

What happens if the problem happens again?
Householders in this position have little choice but to stick with their existing insurer, which is obliged by an industry agreement to continue to offer cover, but inevitably it will increase the premium. It could rise by up to 30 per cent, while the householder may also be subject to a much higher excess.

What happens if I change my insurer?
If you change your buildings insurer and then discover a subsidence-related problem then under the code of the Association of British Insurers, a claim that is made within the first eight weeks of the changeover will be dealt with by the previous insurer. Claims between eight weeks and one year will be handled by the new insurer with the cost of settlement shared equally between the two. Any claims made a year after the changeover means the new insurer alone will deal with the claim.

What if I buy a new property that has subsidence?
All the big insurers continue to offer buildings insurance after subsidence and underpinning, but they may not renew it for a new owner. If potential buyers cannot get insurance, they will not be able to get a mortgage to buy the property.

Does this mean the owners would have to stay in the house forever because they won’t be able to sell the property?
This is when the real problems arise. The owners’ existing insurer isn’t obliged to cover the new owner and many new insurers will run a mile from a property with subsidence problems, even if the problem has been properly repaired. But the ABI says you should be able to get cover from a specialist insurer. But these are more expensive. They are likely to have significantly higher subsidence exclusions requiring you to pay at least the first £2,500 of any claim, possibly higher.

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