What is subsidence?
Subsidence occurs when the foundation of your house collapses or sinks.
This is often caused by:
- Soil, usually clay, shrinking and swelling because of the weather.
- Nearby trees and shrubs absorbing the moisture in the soil beneath your home.
- Leaking drains softening the ground under your home.
It can have consequences for the value of your home and can greatly increase the cost of your home insurance.
- Find out more: the best and worst providers of home insurance, including our Which? Recommended Providers
What are the signs of subsidence?
Your property might be suffering from subsidence if you spot any of the following signs:
- Sudden cracks in plaster and brickwork that are wider at the top than at the bottom
- Doors and widows sticking for no reason
- Rippling wallpaper that isn’t caused by damp
It’s important to note that cracks can appear on walls for varying reasons, so spotting one might not be a cause for panic. 'Settlement' - where a building settles under its own weight - can also cause cracks to appear on walls. This is often seen in newly built homes and extensions.
If a crack is caused by subsidence it will be:
- More than 3mm thick - often getting wider over time
- Wider at the top than at the bottom
- Visible from inside and outside of your home
- Close to doors and windows
Is subsidence covered by home insurance?
Terms and conditions relating to subsidence vary between home insurance providers.
Most home insurers (including all that you will find listed in our table of Best and Worst companies) cover subsidence damage as part of their policy - normally with an excess of £1,000.
Buildings insurance policies usually only cover subsidence damage to the house itself. Areas such as patios, garden walls, driveways and swimming pools aren’t usually covered unless your house is damaged at the same time.
While most policies cover subsidence, if your property has been previously affected, you may find it more difficult to find an insurer that will accept you as a customer.
If you can't find an insurer that will cover you on affordable terms, it may be worth trying a specialist broker.
The British Insurance Brokers' Association can provide further practical advice and can recommend a specialist if you suspect your property has subsidence.
Is my home at risk of subsidence?
Factors that can affect your risk of subsidence include:
Properties built on clay soil are at great risk of experiencing subsidence. Clay soil can shrink, crack and shift during hot, dry weather, making the ground unstable and potentially causing the foundations of your property to sink.
Homes in drought prone areas are particularly at risk of subsidence because the soil is much more likely to dry out.
Trees and shrubs
Trees and shrubs around your home can increase your risk of subsidence. Some species absorb a lot more water which makes the soil much drier.
Subsidence is more common in Victorian and Edwardian houses as their foundations are shallower than the current UK minimum of 1m. This makes them more susceptible to damage from any movements in the ground.
Leaking drains and water mains can increase your risk of subsidence as they wash away or soften soil, causing it compact under the weight of your property over time.
Properties that have had their foundations underpinned may have experienced subsidence previously and are therefore at a greater risk.
Can I reduce my risk of subsidence?
You can reduce your risk of subsidence by taking the following steps:
- Make sure you plant trees and shrubs at least 5-10 metres away from your property
- Prune the branches on your trees regularly
- Keep pipes and drainage systems well maintained to stop water leaking into the soil beneath your house
- Check the surveyor’s report for signs of subsidence before buying a new home
Subsidence: your questions answered
Can subsidence be fixed?
Subsidence is commonly fixed by underpinning - which is the process of strengthening the foundation of a property.
Most home insurance companies offer cover for subsidence related damage but it often comes at a large excess of around £1,000.
If your property has experienced subsidence its risk of happening again increases.
Which trees cause subsidence?
While all trees can put your home at risk of subsidence, some species are more likely to cause problems than others.
Trees with long, fine root structures such as poplars, willows, elms and oaks could dramatically increase your chances of subsidence.
What is heave?
Heave occurs when the ground beneath a building becomes saturated with water and begins to swell - moving upwards and often sideways.
This can cause similar damage to subsidence and is often covered under the same insurance guidelines.
How do I make a claim?
No one wants to have to make a claim on their home insurance but should you be affected by subsidence there are ways to make the process as smooth as possible.
Our making a home insurance claim guide tells you all you need to know about handling the claims process and which home insurance companies stand out from the pack when the going gets tough.
- Find out more: the best and worst home insurance providers