Subsidence in the UK: causes, signs, remedies and how home insurance responds

Subsidence worries many homeowners, especially after hot, dry summers. This guide explains what subsidence is, why and where it happens, how to spot it, what to do next, and how it affects insurance and property value. It also points you to reliable sources for checking local risk and reporting issues.

What is subsidence?

Subsidence is the downward movement of a building’s foundations due to changes in the supporting ground. It differs from settlement, which is expected shortly after construction, and from heave, which is upward movement often after tree removal or soil re-wetting.

Why does subsidence occur?

Common UK triggers:

• Shrink–swell clays: clay soils shrink in dry weather as moisture is lost and can swell again when wet. Repeated cycles cause differential movement.
• Trees and vegetation: large, moisture-demanding trees near shallow foundations can intensify shrinkage in dry spells.
• Leaking drains or water mains: water can wash out or soften soils.
• Mining or soluble rocks: historic coal mining, chalk, gypsum or salt dissolution can create voids.

Where is subsidence more likely?

Risk is higher where shrinkable clays are present near the surface, especially across London and the South-East on London Clay, and where large trees are close to buildings. The British Geological Survey (BGS) maintains national GeoSure datasets that map shrink–swell susceptibility and related ground hazards.

BGS modelling also suggests climate change is likely to increase clay-related subsidence pressures over the coming decades.

How common is subsidence in the UK?

Frequency varies year by year with weather. Measured by insurance activity:

• After the 2018 heatwave, the third quarter alone saw 10,000+ home subsidence claims worth £64 million, the highest quarterly jump since records began.
• In 2022, UK insurers expected around 23,000 subsidence claims costing about £219 million following drought and heat.
• In the first half of 2025, insurers paid £153 million across about 9,000 households, with an average payout of £17,264, after an exceptionally warm spring.

These figures show subsidence is episodic, often spiking after hot, dry seasons.

How to identify possible subsidence

Look for a pattern rather than a single blemish:

1. Cracks wider than about 3 mm, often diagonal and tapered, typically at door or window corners or where extensions join.
2. Doors and windows sticking, rippling wallpaper at joints, uneven floors, or gaps between skirting and floors.

What to do if you suspect subsidence

• Contact your home insurer promptly. Do not start repairs before speaking to them. Most policies require early notification and may appoint a loss adjuster or engineer.
• Document evidence: photographs, dates, and any changes after weather events or tree work.
• Check services: report obvious leaks to your water supplier or a qualified plumber.
• If you are in a former coalfield and mining is suspected, you can also submit a Damage Notice to the Mining Remediation Authority. Tell your insurer if you do this.
• Do not fell or prune protected trees without consent. Many UK trees are protected by Tree Preservation Orders or conservation-area controls. Apply to the local council if consent is needed.

Remedies and repairs

Remediation depends on the cause and severity:

• Tree and vegetation management: pruning, species change or, in some cases, removal with council consent if protected. Root barriers may be considered.
• Fixing leaks and drainage defects: re-lining or replacing damaged pipework can stabilise soils.
• Soil stabilisation or underpinning: from targeted resin or grout injections to traditional underpinning or piled foundations for severe cases. These are engineered solutions following investigation.

Your insurer or appointed engineer will recommend the least invasive effective option. Average claim costs vary by year. Many claims are resolved without underpinning.

Will subsidence affect property value?

Yes, it can. Devaluation depends on severity, cause, quality of repair, warranty length and monitoring records. Well-documented, engineered repairs with completion certificates and transferable guarantees typically reduce the impact at resale compared with unresolved or recurring movement. A surveyor can advise for your property and local market.

Can you look up historical or geographical subsidence risk?

Yes. Useful sources when buying, selling or managing risk:

• BGS GeoSure datasets show shrink–swell and other natural ground hazards. Commercial searches and BGS reports are available.
• Coal Authority and CON29M mining searches reveal past coal-mining activity and recorded subsidence claims near a property.
• A local RICS surveyor can interpret results and investigate site-specific causes.

How home insurance treats subsidence

• Existing policies: Buildings insurance often covers subsidence, heave and landslip as a named peril, subject to an excess and conditions. Contents are typically only affected if damaged by the event.
• Claims handling: expect monitoring through a season, repair of the cause, then structural repair. Some cases take time to confirm movement has stopped.
• After a claim: many insurers continue cover but may apply terms or endorsements. If mining is responsible, the Mining Remediation Authority may handle compensation. Tell your insurer if you make that claim.

Helpful external resources

• RICS consumer guide to subsidence (what surveyors look for).
• BGS GeoSure datasets on shrink–swell and soluble rocks.
• Coal mining subsidence claims and rights (GOV.UK).
• Tree Preservation Orders guidance (GOV.UK) before any tree work.
• ABI statistics on recent subsidence claim trends.

Frequently asked questions

What are the first signs of subsidence?

Diagonal, tapered cracks wider than about 3 mm, sticking doors or windows, rucking wallpaper and gaps at skirtings are typical red flags. Get a surveyor to confirm.

Are certain house types more at risk?

Homes with shallow Victorian or Edwardian foundations on shrinkable clay, especially near mature trees, are commonly affected after dry summers.

Does insurance always cover subsidence?

Most buildings policies include it, but terms, excesses and exclusions vary. Report concerns early and follow your insurer’s process before repairs.

Can removing a tree make things worse?

Yes. Removing large trees on clay can cause heave as soils re-swell. Seek professional advice and council consent if the tree is protected.

How long does a subsidence claim take?

Many cases require monitoring over seasons to confirm stability before final repairs. Timelines depend on cause and evidence thresholds set by engineers and insurers.

How do I check local subsidence risk before buying?

Order conveyancing searches and consider a BGS GeoSure-based report. In former coalfields, include a Coal Authority mining search. Commission an RICS surveyor to interpret findings.