Subsidence map: The areas most at risk of ground movement
Subsidence claims: The numbers
- £307 million - What insurers paid out on subsidence claims in 2025. A new record.
- Around 1 in 10 - Share of British land on the worst-classified subsidence soil.
- £17,000 - Average subsidence pay-out. More than any other home insurance claim.
Subsidence risk map
Each hexagon represents 65 km² of British land, classified by the British Geological Survey for shrink-swell subsidence risk.
What the three classes mean
| Colour | Type | What it means | What you'd notice |
|---|---|---|---|
| Green | Low | The ground rarely shifts. | Low risk of impact. |
| Orange | Moderate | Some clay in the soil. | Hairline cracks after a long dry spell. |
| Red | Significant | Worst-classified soil. | Cracks, sticking doors, walls moving - usually after a hot summer. |
Check your area’s subsidence risk
Type the name of your town, city or council. We'll show you the subsidence-risk profile for that exact urban area, based on every 0.25 km² inside its boundary.
What to do if you’re in a higher risk area
If you're in Moderate or Significant ground, it's worth checking if your home insurance covers subsidence.
Most policies do, but the excess (the bit you pay before the insurer covers the rest) is usually higher than for other claims.
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What is subsidence?
Subsidence is when the soil beneath your home shrinks and drags the foundations down with it. As the ground sinks, walls crack, door frames warp and floors tilt slightly.
In the worst cases it's expensive enough to need underpinning, which is a serious engineering job to stabilise the foundations.
While this may sound catastrophic, it can be easily managed and prevented.
Most British homes will never see it. But the homes that do tend to be in a specific geological band that runs through the south and east of England.
Unfortunately, if it does happen, it can often leave you with one of the biggest bills of any home insurance claim.
What causes subsidence?
In short, some soils contain clay minerals that act like sponges.
- When it rains, the clay absorbs water and swells.
- When it dries out, the clay loses water and shrinks.
If your home sits on this kind of clay, the ground beneath the foundations expands and shrinks with the weather. Most of the time you'd never notice. The movement is gradual, the seasons balance out.
The trouble can start after a really hot, really dry summer. The clay dries deeper and shrinks harder than the foundations can handle, and the building twists slightly with the soil. That twist causes the cracks you see in your walls.
The opposite, where soil swells and pushes the foundation up, is called heave. Same mechanism, different direction.
Whether your home is exposed depends almost entirely on the soil beneath it.
It's why Cornwall (granite bedrock, no clay) is safe, but Bromley (London Clay) isn't.
How to spot subsidence
Subsidence happens gradually, so you won't wake up one morning and find half a wall missing.
The earliest signs are subtle:
- Diagonal cracks in walls, especially around door frames, window frames or where extensions meet the original house. Hairline cracks are normal in any home. The flag is when a crack is wider than 3mm (about the width of a pound coin's edge) and runs diagonally
- Doors and windows that suddenly stick, even though they used to close fine
- Cracks visible from inside and outside on the same wall
- Cracks that get wider in summer and narrower in winter, or the other way round
- Wallpaper rippling at the corners of door frames
- Floors tilting noticeably, especially in extensions
Most cracks are not subsidence. Cracks above doors and below windows are usually just thermal movement, or settlement in a relatively new building.
The diagonal direction, the size and the seasonality together are what flag subsidence specifically.
What to do if you suspect subsidence
You shouldn’t panic and contact your insurer immediately. It’s actually better to wait.
If you’re looking for some steps to take, we’d recommend:
- Photograph the cracks. Note the date, location and width. If they're not changing month to month, you probably don't have a subsidence problem.
- Watch for six months. Subsidence cracks usually move with the weather. If a crack is the same width in June and December, it's most likely cosmetic.
- If the cracks are changing, call a chartered surveyor, not your insurer. A surveyor will diagnose what's actually going on. Many "subsidence" cases turn out to be drainage issues, tree-root damage or thermal movement, all of which are treated differently.
- If the surveyor confirms subsidence, then call your insurer. Be ready: subsidence claims have higher excesses than other claims (often £1,000+) and take longer to settle.
Is subsidence getting worse in the UK?
Subsidence claims aren't new, but they're getting bigger and more frequent. The reason is the weather, not the geology.
The hottest UK summers on record are clustering in the last decade. 2018, 2020, 2022 and 2025 all triggered record waves of subsidence claims. The ABI's payout numbers have climbed each time.
£307 million in 2025 was a new high.
The British Geological Survey's modelling expects dry summers to become more common. In a 2021 BGS report, the share of UK homes at risk of subsidence damage was projected to rise from around 3% in 1990 to roughly 10% by 2070. In London, the share could rise from 20% in 1990 to 43% by 2030, and 57% by 2070.
What those rising numbers really mean is that more homeowners are likely to be caught out, often by policies that don't fully cover subsidence or that carry a high excess when they do. As the risk spreads, more people will find the gap between what they assumed they were covered for and what they actually are.
That's why we built this page.
What subsidence means for your home insurance
In nearly every UK home buildings insurance policy, subsidence is one of the standard "perils". Same list as fire, flood, theft and burst pipes. It's been a standard inclusion since the late 1970s.
The high costs come from the excess.
Why subsidence has its own excess
For most claims (a stolen TV, a burst pipe, a damaged window), your insurance excess is somewhere in the £100 - £250 range.
Subsidence excesses are usually much bigger. Most policies set the subsidence excess at £1,000. Some go to £2,500 or higher, especially on older homes or in higher-risk postcodes.
This isn't a hidden trick. It's there to discourage trivial claims, since subsidence is structural and an insurer's investigation alone can cost a few thousand. The high excess weeds out cosmetic crack claims and keeps the cover affordable for everyone else.
But it means a real subsidence claim still costs you four figures before the insurer covers the rest. Worth knowing before you call.
What insurers ask before they quote
When you compare quotes for home insurance, you'll be asked one or two subsidence-specific questions:
- Has the property ever suffered subsidence, heave or landslip?
- Is the property currently being monitored for any of these?
If your home has a history, insurers will either price it higher, ask for more detail, or refer you to a specialist. They won't necessarily refuse. The big mistake is failing to declare. Withheld history is a leading reason claims get denied later, even on routine matters that have nothing to do with subsidence. Be honest at quote time.
If you have no history and your postcode happens to be in a higher-risk area, that on its own doesn't usually load your premium. Insurers price on actual home characteristics first, geological risk second.
Buying a house with previous subsidence
Worth saying clearly: a home with a settled, repaired and certified subsidence history is not necessarily a bad buy. Most lenders will mortgage it and many insurers will cover it. The price will reflect the history, which usually means it's cheaper than it would be otherwise.
What you'll want from the seller:
- The engineer's report from the original investigation.
- Evidence of completion (the work signed off).
- A structural warranty if underpinning was done (usually 10 to 12 years).
- Continuity of insurance: has the property been insured continuously since the work? Gaps in coverage make new policies harder to get.
Your conveyancer should ask for all of these. If anything's missing, factor it into your offer.
If you're already a homeowner and worried
Brief recap from above: photograph the cracks, watch for six months, call a chartered surveyor before you call your insurer.
Calling the insurer first puts a "subsidence enquiry" on your record. Even if it turns out to be nothing (drainage, thermal movement, normal settlement), that note can affect your renewal premium. A surveyor's diagnosis lets you know what you're actually dealing with before you tell anyone.
If the surveyor confirms subsidence, then yes, call the insurer. Most will manage the whole process, from monitoring through to (if needed) repair and underpinning. The £1,000+ excess hurts, but the rest of the bill, often £20,000 to £60,000, is theirs.
FAQs
How much does it cost to fix subsidence?
It varies widely. Cosmetic fixes like filling cracks and redecorating might be a few hundred pounds. A monitoring period plus minor repairs typically runs £2,000 - £5,000.
Underpinning (the heavy-engineering option) usually costs £10,000 - £25,000 for a small house, more for larger or complex properties.
The ABI says the average UK subsidence claim payout in 2025 was around £17,000.
Can you sell a house with subsidence?
Yes. Properties with a documented, repaired and certified subsidence history sell every day.
You'll need to disclose the history, provide the engineer's reports and any structural warranty, and accept that the price will reflect the history. Buyers and lenders both generally accept settled and certified cases.
Active, unresolved subsidence is much harder to sell.
Can I get a mortgage on a house with subsidence?
Often yes, with conditions.
Mainstream lenders will usually mortgage a property with a settled and certified history. Some may require additional surveys or a higher deposit. Properties currently being monitored (mid-investigation) are harder to mortgage.
If standard lenders refuse, specialist lenders cover this market, though you can expect higher rates.
What's the difference between subsidence and settlement?
Settlement is the gentle, expected sinking that most buildings do in their first few years. It's normal and rarely needs fixing. Subsidence is the unexpected ongoing movement of foundations due to soil change, usually shrink-swell clay.
The distinction matters because one is simply a phase a building passes through as it beds into the ground, while the other is an active problem that tends to worsen without intervention.
Do trees cause subsidence?
They can.
Tree roots draw moisture from the soil, and on shrink-swell clay that drying causes the same shrinkage as a hot summer. The mature tree planted three metres from your kitchen extension is a classic culprit.
Removing trees too quickly can cause the opposite problem (heave), so if trees are involved, paying for an arboriculturalist's advice could help in your situation.
Does subsidence ever stop on its own?
Sometimes.
Subsidence caused by a one-off event (a leaking drain that's fixed, a problem tree that's managed) often resolves when the cause is removed.
Subsidence on shrink-swell clay tends to recur with the weather, but it doesn't necessarily get worse. Many properties have minor seasonal movement for decades without ever needing structural repair. A surveyor's diagnosis tells you which kind you've got.
Will subsidence affect my house value?
Yes, while it's active or recent.
A property with live, undiagnosed cracks will be hard to sell at full market price. A property with settled, certified, repaired subsidence usually sells at a 5-15% discount versus an equivalent home with no history.
A property where the work was done decades ago and no longer affects insurance often sells at no discount at all.
How long does a subsidence repair take?
Most subsidence cases go through a monitoring period before any structural work is decided. That alone is typically 6-12 months.
If underpinning is needed, expect another 2-4 months of work plus several weeks of redecoration. Cosmetic-only cases (no underpinning) can be done in weeks. The whole process, from first crack to closed claim, is usually 12-24 months.
Are new builds at risk of subsidence?
New builds are designed to modern foundation standards that mostly prevent subsidence, especially on known-risky soil. But they're not immune.
New builds on shrink-swell clay can still see seasonal movement, and an undetected drain leak or root incursion can affect any home. The NHBC 10-year warranty covers structural defects on new builds, including subsidence-related issues during that window.
Methodology and sources
The short version: we took the British Geological Survey's national subsidence dataset, matched every patch of UK land to its council and its town, and ranked the results.
Below is the long version.
Data sources
- British Geological Survey (BGS) GeoSure 5km hex grid, version 8. Open Government Licence, via Ordnance Survey Data Hub. 4,233 hexagonal cells covering Great Britain, each classified Low, Moderate or Significant for shrink-swell hazard.
- ONS Local Authority Districts (December 2025) UK BGC. 361 UK council boundaries. Open Government Licence.
- ONS Built-Up Areas (December 2022) GB BGG. 8,545 UK city, town and village boundaries. Open Government Licence.
- Association of British Insurers (ABI) claims data. Public press releases, including the record £307 million in 2025. The £17,000 average payment data found here.
Method
We generated a fine grid of points across the UK (500m spacing for the city/town view, 1km spacing for the council view). For each grid point, we tested which BGS hex contained it (giving its risk class) and which council and built-up area contained it (giving its geographic context). Aggregating per place gives the area in km² in each risk class.
This is the same areal apportionment approach the ONS uses when re-allocating data between geographies. It captures partial overlaps that a simple centroid match would miss.
What this doesn't say
- The data is at 5km grid resolution. It is not suitable for individual property advice. A specific home's risk depends on its exact soil, foundations, age, drainage and tree proximity.
- BGS GeoSure covers Great Britain only. Northern Ireland isn't included in this analysis.
- Smaller built-up areas (under a few km²) may sit entirely inside a single BGS hex, so they take that hex's class for their whole footprint.
- BGS GeoSure is updated periodically by the British Geological Survey. We used version 8.