Subsidence is the downward movement of the ground beneath a building, causing the foundations to sink unevenly and the structure to crack or shift. It's different from settlement (which is normal gradual movement after construction). Common causes in the UK include clay soil shrinkage (especially during dry summers), tree roots absorbing moisture near foundations, leaking drains, and mining activity.

Does home insurance cover subsidence UK?

Most standard home insurance policies cover subsidence, but with conditions. There's typically a higher excess specifically for subsidence claims — usually £1,000 (the standard for most policies). However, if you've had previous subsidence, finding affordable insurance is much harder. Some policies exclude subsidence entirely, and you must always declare previous subsidence when applying for insurance.

How much does subsidence repair cost UK?

Subsidence repair costs depend on the cause and severity. Tree removal may solve the problem for £500–£5,000. Drain repairs cost £1,000–£5,000. Underpinning (the most serious option) costs £10,000–£50,000+ depending on the property size and method. In most cases (70%+), underpinning is NOT required — removing the cause and monitoring is sufficient.

Can I sell a house with subsidence UK?

Yes, but it's harder and usually results in a lower price. If subsidence has been resolved and you have a certificate of structural adequacy, the impact on value is reduced (typically 10%–20% lower). If ongoing or unresolved subsidence, the discount can be 20%–50%. You must declare subsidence history to buyers, and their mortgage lender will require a structural survey.

Subsidence UK — Signs, Insurance, Costs, and What to Do | PocketWise

Subsidence affects an estimated 1 in 5 UK homes to some degree, particularly in areas with clay soil. It can be frightening — but in most cases, it’s manageable without underpinning, and insurance covers the cost.

What Causes Subsidence?

Cause	How it happens	Prevalence
Clay soil shrinkage	Clay shrinks in dry weather, causing ground to drop	Most common — especially South East England
Tree roots	Roots absorb moisture, drying the soil and causing shrinkage	Very common near mature trees on clay
Leaking drains	Water washes away or softens soil beneath foundations	Common
Mining	Historical mining activity creates voids underground	Specific areas (Midlands, North, Wales)
Poor original foundations	Older properties may have shallow foundations	Pre-1950s properties
Prolonged dry weather	Dry summers cause clay to shrink	Increasing with climate change

Signs of Subsidence

Sign	What to look for
Diagonal cracks	Wider at the top than the bottom, often near windows/doors
Crack width	Cracks wider than 3mm (thickness of a 10p coin edge)
New cracks appearing	Especially after dry weather
Doors and windows sticking	Frames distorting as walls move
Wallpaper crinkling	At wall-ceiling joints
Cracks that worsen over time	Old cracks reopening or widening

Not All Cracks Are Subsidence

Crack type	Likely cause	Subsidence?
Hairline cracks (under 1mm)	Normal settlement, temperature changes	Unlikely
Cracks around recent work	Plaster shrinkage, building work	No
Horizontal cracks	Lateral movement, wall tie failure	Different issue
Cracks above windows/doors, wider at top	Subsidence pattern	Possibly
Cracks with ongoing widening (monitor with tell-tales)	Subsidence	Possibly

What to Do if You Suspect Subsidence

Step	Action
1	Don’t panic — most cases don’t need underpinning
2	Monitor the cracks — photograph them, measure with a ruler, mark with pencil and date
3	Contact your buildings insurer — report the suspected subsidence
4	Insurer sends a surveyor — they’ll assess the cause and severity
5	Investigation — drain surveys, soil analysis, tree surveys, monitoring
6	Treatment — based on the cause (see below)

Investigation

Assessment	What it involves	Cost (if paying privately)
Structural survey	Surveyor examines cracks and structure	£400 – £1,000
Crack monitoring (tell-tales)	Gauges fitted across cracks, monitored over 12+ months	£100 – £500
Drain survey (CCTV)	Camera inspection of drains	£200 – £500
Soil investigation	Trial pits or boreholes to analyse soil conditions	£500 – £2,000
Level survey	Precise measurement of floor/wall levels	£300 – £800
Tree survey	Arborist assessment of nearby trees	£200 – £500

Note: If you claim on insurance, the insurer arranges and pays for investigations.

Treatment Options

Treatment	When used	Cost	Success rate
Tree management/removal	Tree roots causing soil shrinkage	£500 – £5,000	High
Drain repair	Leaking drains washing away soil	£1,000 – £5,000	High
Root barriers	Preventing root growth under foundations	£2,000 – £5,000	Good
Monitoring only	Minor movement that stabilises	Minimal	Many cases resolve
Underpinning	Severe cases where foundation must be strengthened	£10,000 – £50,000+	Very high

Underpinning Methods

Method	How it works	Cost
Traditional mass concrete	Excavate beneath foundations, fill with concrete in stages	£10,000 – £30,000
Mini-piled	Drive piles deep into stable ground	£20,000 – £50,000
Resin injection	Inject expanding resin to stabilise soil	£5,000 – £15,000

Important: Over 70% of subsidence cases do NOT require underpinning. Most are resolved by addressing the cause (tree removal, drain repair) and monitoring.

Insurance and Subsidence

Standard Cover

Feature	Detail
Buildings insurance	Most policies include subsidence cover
Standard excess	£1,000 (industry standard for subsidence claims)
What’s covered	Investigation, monitoring, repairs, redecoration
What’s not covered	Pre-existing subsidence known at purchase
Claim timeline	Can take 12–24 months to fully resolve

Previous Subsidence Claims

Impact	Detail
Higher premiums	Significantly more expensive
Higher excess	Some policies set £2,500 – £5,000 excess
Limited choice	Fewer insurers will cover the property
Specialist insurers	May need to use specialist property insurance
Must declare	Always declare previous subsidence when applying

Getting Insurance with Subsidence History

Strategy	Detail
Use a specialist broker	They know the market
Provide completion documentation	Certificate of structural adequacy, monitoring reports
Show the problem is resolved	Long-term monitoring proving stability
Compare specialist insurers	Some specialise in non-standard properties

Buying a Property with Subsidence History

Check	What to look for
Certificate of Structural Adequacy	Confirms repairs were done properly
Insurance history	What was claimed, how it was resolved
Monitoring records	Show stability over time
Surveyor’s report	Get a full structural survey (not just a homebuyer’s report)
Insurance availability	Check you can get affordable insurance before buying
Price discount	Expect 10%–20% below comparable properties (resolved subsidence)

Selling with Subsidence History

Factor	Impact
Must declare on the TA6 form	Property Information Form asks directly
Price impact (resolved)	10%–20% reduction
Price impact (unresolved)	20%–50% reduction
Buyer’s mortgage	Lender will require a structural survey
Supporting documents	Certificate, monitoring data, insurance claim records

Subsidence Risk Areas

Region	Risk level	Reason
South East England	High	Clay soil
London	High	London Clay formation
East Anglia	Moderate to High	Clay and peat soils
Midlands	Moderate	Some clay, historic mining
South West	Low to Moderate	Mixed geology
North West	Moderate	Mining legacy
Wales	Moderate	Mining areas
Scotland	Low	Generally stable geology

Prevention

Measure	Detail
Tree management	Keep trees at least their mature height distance from the property
Drain maintenance	Regular inspection and repair of drains
Gutters and downpipes	Keep clear to prevent water pooling near foundations
Don’t pave right up to walls	Allow some permeable ground for drainage
Monitor cracks	Early detection saves money
New trees	Plant at safe distance from buildings (species-dependent)

Summary

Key point	Detail
Most common cause	Clay soil shrinkage + tree roots
Warning signs	Diagonal cracks wider than 3mm, doors/windows sticking
First step	Contact your buildings insurer
Most cases	Resolved WITHOUT underpinning (70%+)
Underpinning cost	£10,000 – £50,000+
Insurance excess	£1,000 standard for subsidence
Impact on value	10%–20% (resolved), 20%–50% (unresolved)
Best prevention	Tree management and drain maintenance