As a homeowner, the sight of a large crack in a wall should set the alarm bells ringing — it could be a sign of subsidence.
Other things to look out for are wallpaper tearing and doors and windows becoming difficult to open.
Subsidence is when the ground beneath your property sinks because the soil is unstable, and pulls the foundations of the building down with it.
But what can you do if your house is at risk of subsidence? Here we take a closer look.
Is my home at risk?
Subsidence can be caused by a variety of factors including soil type and local mining activity.
Properties built on clay are especially susceptible to subsidence and matters can get exacerbated over long, dry summers when trees and shrubs take all the moisture from the soil, causing houses to shift on their foundations.
Many homes in London and the South East are built on clay soil.
New research by Groundsure, a firm which carries out environmental searches, suggests that 41% of properties in Nottingham could also be at risk of subsidence due to the expansive network of former sandstone mines and tunnels throughout the city council area.
The firm has carried out similar research in other cities, too. It warns that more than a million properties in Greater Manchester are at risk of ground movement due to disused mine shafts in the area, while in Bristol, 170,000 properties are at risk for the same reason.
Other factors which could be an issue in terms of subsidence include trees and shrubs located close to foundations, as well as leaking drains and water mains.
How can I spot it?
The first sign of subsidence is typically distinctive diagonal cracks in a wall which are wider at the top and thicker than the width of a 10p coin.
Other signs to watch out for include doors or windows which stick for no reason, or close easily in winter, but not in summer and wallpaper which is tearing, but not caused by damp.
Can I prevent it?
There are steps you can take to try and reduce the risk of subsidence, such as pruning trees and large shrubs to prevent soil from drying out, and also laying porous materials such as gravel or grass around the building to allow water to drain naturally.
In addition, you should check water pipes and guttering for leaks which can soften soil or wash it away.
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Martin Miliner, claims director at insurer LV=, said: “It’s a good idea to carry out any precautions in your home, as making small changes early on can help make a difference.”
It’s also worth checking your buildings insurance to find out exactly what you’re covered for.
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What should I do if I spot it?
If you think your home has suffered from subsidence damage, you should speak to your insurer at the earliest opportunity to minimise expense. They will advise you on the relevant course of action.
This may involve a specialist coming out to your home to examine the damage and determine its cause.
According to the Association of British Insurers, if the damage is minor, repairs will usually be carried out straight away. However, if the damage is severe and the subsidence ongoing, the movement of your home may need to be monitored so engineers can work out a long-term solution.
In extreme cases, your home may need to be underpinned. This is where the foundations are strengthened to prevent further subsidence.
Will my insurance cover me?
Generally speaking, your insurance policy will cover you for damage caused to the structure of your property.
Some policies may also include cover if you need to move out of your home while work is carried out.
Note that claims for subsidence can easily run to several thousand pounds, and sometimes even tens of thousands of pounds.
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There will usually be an excess of around £1,000 ($1,354) on a subsidence claim. That’s the amount you would need to contribute towards the cost of any claim you make.
After repairs have been carried out, insurers will tend to continue to offer subsidence cover, as long as the repairs have been carried out to their required standard.
However, you might face a higher premium going forward — or a significantly increased excess on further claims.
Kevin Pratt, insurance expert at Forbes, said: “When you buy insurance, you’ll be asked whether the property has previously suffered from subsidence. If it has, there’s a chance you might struggle to find an insurer that’s willing to take you on, and any that do will likely charge a higher premium and impose a hefty excess of up to £5,000.”
What if I’m buying a property with past subsidence issues?
If the home you’re hoping to purchase has suffered from subsidence, you need to check repair work has been carried out correctly. A surveyor and conveyancer will investigate this as part of your house purchase.
Your lender may require a transferable warranty for the work that’s been done.
You should also check whether you will be able to get buildings insurance from a mainstream insurer, as if your only option is a specialist insurer, this could prove to be pricey.
What if I’m trying to sell?
According to research by LV=, almost half of homeowners (43%) would still consider buying a property with a history of subsidence. However, of this number almost a third (29%) would only commit to a property if a building survey confirmed it was safe. A further 7% said they would strategically use it to negotiate a price cut.
Another 7% of homebuyers said they wouldn’t be concerned at all.