Signs of Subsidence: How to Spot & Fix It (2026 Guide)
What is subsidence?
Subsidence is one of the most feared words in property — but it's also one of the most misunderstood. Not every crack means subsidence, and most cases can be resolved. Knowing the genuine warning signs helps you act calmly, protect your home's value, and sell successfully if you need to.
The common signs of subsidence (checklist)
- Diagonal cracks wider than 3mm — typically running from windows and door corners, and visible inside and outside.
- Cracks wider at the top than the bottom — a classic tapering pattern.
- Doors and windows sticking — as frames distort out of square.
- Sloping or uneven floors — noticeable with a spirit level or a rolling marble.
- Rippling wallpaper at wall/ceiling joints, not caused by damp.
- Cracks where an extension meets the main house — where foundations differ.
What causes subsidence?
Subsidence occurs when the ground loses its load-bearing capacity. The main causes are:
| Cause | How it works | Common where |
|---|---|---|
| Clay shrinkage | Clay soils shrink in dry weather, removing support | South & east, dry summers |
| Tree roots | Roots draw moisture, shrinking nearby clay soil | Trees close to the building |
| Leaking drains | Escaping water washes away or softens soil | Older drainage runs |
| Historic mining | Old workings collapse beneath the surface | Former Scottish coalfields |
| Made-up ground | Building on poorly compacted fill | Reclaimed or infill sites |
Key takeaways
- Diagonal cracks over 3mm, sticking doors and sloping floors are the key signs.
- Common causes: clay shrinkage, tree roots, leaking drains and old mine workings.
- Most subsidence is fixable — often without underpinning.
- Buildings insurance usually covers subsidence (subject to an excess).
- Homes with subsidence often sell best at auction to cash buyers.
How is subsidence fixed?
The right fix depends on the cause. Many cases are resolved simply by removing the cause — felling or managing a tree, or repairing a leaking drain — and then making good the cracks once movement stops. More serious cases may require underpinning, where the foundations are strengthened or deepened. A chartered structural engineer's report is the essential first step; never panic-underpin without one.
Subsidence and buildings insurance
Buildings insurance in the UK typically covers subsidence, though usually with a higher excess (often around £1,000). Crucially, a property with a history of subsidence can be harder — and costlier — to insure and mortgage, which narrows the pool of buyers on the open market. Keep all documentation: the engineer's report, any monitoring, the cause identified, and the certificate of completed remedial works.
Subsidence in Scotland: former coalfields and mining
Subsidence in Scotland often has a different cause from the clay-shrinkage cases common in the south of England. Large parts of the Central Belt — including areas of Lanarkshire, Ayrshire, Fife, West Lothian and Falkirk — sit above historic coal workings, and disused shallow mine shafts or galleries can still settle today. If you are buying or selling in a former coalfield, a Coal Authority mining report (and, where flagged, a follow-up assessment) is the document that lenders and solicitors will expect to see.
Because Scotland's market relies on the Home Report, any visible movement or known mining history is likely to be picked up by the surveyor and reflected in the single survey — so disclosing early and having the paperwork ready protects your timeline. As of 2026, the Coal Authority's free interactive map lets you check quickly whether a property falls within a defined coalfield area before you commission a full report.
Can you sell a house with subsidence?
Yes — but full disclosure is essential, and the method matters. Because subsidence limits mortgage options, these homes can be slow and frustrating to sell traditionally. At auction, cash buyers, developers and investors who are comfortable with structural work compete for the property — delivering a fast, certain sale without endless renegotiation.
If your home has cracks or a subsidence history and you'd rather not wait, see what to do with an unmortgageable home or get a free, no-obligation auction valuation.
Founder & Director of Scotland Property Auction. Julie has spent over a decade helping Scottish homeowners, landlords and executors sell property quickly at auction — covering Home Reports, missives, repossession and the modern method of auction.
More about Julie →✔ Last reviewed June 2026 by Julie McAndrews. We keep our guides current with Scottish property law and market conditions.