What Is Subsidence and How Does It Affect Your Home?
Subsidence happens when the ground beneath a property moves downwards, causing the foundations to lose support. As the structure settles unevenly, cracks appear, floors slope, and windows or doors may jam.
It’s a serious problem that affects thousands of UK homes every year, particularly those built on clay soil or older buildings with shallow foundations.
Subsidence isn’t the same as settlement. Settlement is natural and usually happens soon after construction as the soil compresses under the weight of the building. Subsidence, on the other hand, is ongoing — it gets worse if ignored.
What Causes Subsidence in Houses?
In the UK, most subsidence comes down to how the ground reacts to changes in moisture and pressure. Clay soils are a major factor — they swell when wet and shrink as they dry, especially after long hot summers, which can pull away from the foundations and leave them unsupported. Trees and large shrubs make matters worse by drawing moisture from the surrounding soil, with thirsty species such as oak, willow and poplar known for leaving the ground unstable. Leaking drains or damaged underground pipes can also wash away the fine material that supports your home, gradually softening the soil beneath. And in some parts of the country, old mining tunnels or filled-in landfill sites can collapse over time, creating voids that cause the ground above to sink.
How to Spot Early Warning Signs of Subsidence
Not every crack points to subsidence — but the pattern often tells the story.
Diagonal cracks that widen toward the top of a wall are a classic early sign, particularly around doors and windows. If you can see the same crack running through internal and external walls, it suggests the whole structure is shifting. You might also notice doors or windows beginning to stick, or floors that suddenly feel uneven. Creases in wallpaper near ceiling joints without any signs of damp can hint at structural movement, and cracks appearing where an extension meets the main house can reveal that the two parts of the property are moving differently.
If several of these symptoms show up together, it’s worth getting a professional assessment. Surveyors often monitor cracks over time to confirm whether the movement is ongoing or historic.
Does Home Insurance Cover Subsidence Damage?
Most standard home insurance policies include subsidence cover, but it’s rarely straightforward. Claims typically carry a higher excess than normal, and insurers expect full disclosure if your home has experienced subsidence before. Failing to mention it can void a policy altogether.
Homes that have been underpinned or previously affected may also need specialist insurers, often at a higher premium. If you do need to make a claim, insurers will usually arrange for a structural assessment. If subsidence is confirmed, they may cover repairs and even temporary accommodation while work is carried out. Just keep in mind that premiums often rise after a claim, and some insurers may decline cover for homes with a known history.
The Best Ways to Repair Subsidence in a Property
Repairing subsidence depends on its cause and severity. In some cases, reinforcing or deepening the foundations — known as underpinning — may be necessary, though it’s not always the first choice if movement is localised. Modern methods such as resin injection can also help, with expanding resin filling voids and stabilising the soil beneath.
If leaking drains or pipes are to blame, fixing these can prevent further damage. And where tree roots are drawing moisture away, pruning or removal might be needed — though it must be handled carefully to avoid heave, where the ground lifts after roots are gone. Once movement has stopped, any cracks or structural damage can be repaired to restore stability.
How to Prevent Subsidence in Your Home
While subsidence can’t always be avoided, a few sensible habits can lower your risk. Avoid planting large trees close to your home, especially on clay soil. Check drains regularly for leaks, and repair them promptly. Keep an eye out for new cracks or uneven floors, particularly in older properties or those in high-risk areas. And if something doesn’t look right, act early — getting professional advice quickly can stop a small issue becoming a costly one.
Final Thoughts
Subsidence can sound alarming, but it’s a problem that can be managed. With early detection, good maintenance, and modern repair methods, most homes can be stabilised and restored without lasting impact.
If you’re concerned about movement in your property, our team at Harrison Clarke can assess your home, identify the cause, and recommend the right next steps.
Call 02381 550051 to speak to one of our chartered surveyors today.
For more expert advice on surveying and property matters, check out our range of informative videos on our website or YouTube channel. Harrison Clarke Chartered Surveyors is here to guide you every step of the way!
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