What is subsidence?
Subsidence happens when the ground your house is built on drops or moves. It might be because the soil has a high clay content which, when it dries out, can causes problems. There may be mines or natural underground phenomena which cause movement. A relatively common cause could be that a large tree nearby has roots that are affecting the foundations of your house, or sometimes leaky pipes underground can wash soil away under the foundations. Houses with shallow foundations are more at risk of subsidence – these tend to be Victorian or Edwardian.
There are some things we just have no control over, but any measures to reduce the risk of subsidence are worth looking at.
Trees and vegetation may look attractive around a home, but they could be doing something very ugly underground. If you have large trees or vegetation very close to your house, it may be well worth having them looked at by a professional, so they can be managed. Contrary to what you might think, chopping them down could actually cause more damage.
Keeping an eye on your pipes above ground to make sure they’re not leaking will help. Clearly you can't see what's going on underground, though.
Signs of subsidence
Movement in a house is normal, particularly as the seasons change. You can often find small hairline cracks around the house, and perhaps surprisingly, this is even more likely if it's quite a new home.
But there are some more dramatic structural signs that should give you an early warning and are best investigated by a Structural Engineer. Things you could look out for:
- Cracks that move depending on the season
- Vertical or diagonal cracks all in a certain area.
- Cracks that go through the damp proof course and into foundations
- Windows and doors sticking
- Cracks that can be seen both internally and externally
How do you fix it?
Contact your insurer first for advice. They might appoint a structural engineer to assess the damage, and that way everyone will know what they're dealing with. Subsidence isn't always the massive deal we might worry about. You may not even need to have too much structural work and underpinning is not always needed.
Your buildings insurance should cover subsidence but each policy has different exclusions, so you'd need to ring them to find out. It's also worth noting that the excess for subsidence is often quite high.
Do I need specialist subsidence home insurance?
Once a property has been affected with subsidence, even though it's likely you might not experience problems again it'll probably impact your property insurance. Don't worry though, you should still be able to find a company to insure you. Be warned - your premiums are likely to rise and you may find you would be better to stay with your current insurer.
There are also specialist subsidence insurance firms that are happy to insure homes that have suffered, or are at risk of suffering subsidence. The best thing to do is shop around, do a home insurance comparison search every year and don't assume you should stay with your insurer.