Condition
What Causes Subsidence?
Subsidence is the downward movement of the ground beneath a property, causing the foundations to sink. The main UK causes are clay-soil shrinkage in dry weather, tree and shrub roots drawing moisture from the soil, leaking drains washing soil away, and ground conditions like old mine workings or made-up ground. The tell-tale signs are diagonal cracks wider than 3mm. Understanding the cause is the first step to fixing it — and to selling an affected home.
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- Clayshrinkage, top cause
- Over 3mmdiagonal crack sign
- 7-28 dayscash as-is
The main causes of subsidence
| Cause | How it works |
|---|---|
| Clay shrinkage | Clay soil shrinks in dry weather, ground sinks |
| Trees & shrubs | Roots draw moisture, shrinking clay soil |
| Leaking drains | Escaping water washes away or softens soil |
| Mining / made-up ground | Old workings or poorly compacted fill collapse |
| Soft / variable ground | Uneven support for the foundations |
Clay shrinkage, often combined with nearby trees, is the most common UK cause.
Clay soil and trees
The most frequent cause in the UK is shrinkable clay soil: in dry spells the clay loses moisture and shrinks, and the ground beneath the foundations sinks. Trees and large shrubs make this worse, as their roots draw large amounts of water from the soil, accelerating the shrinkage — which is why subsidence often appears near trees in hot, dry summers. This is also why managing (not necessarily removing) nearby trees can be part of the solution.
Water and ground conditions
Leaking drains or water mains are another common cause: escaping water can wash away fine soil particles or soften the ground, undermining the foundations. And the ground itself matters — old mine workings, poorly compacted "made-up" ground from past development, or naturally soft or variable soils can all provide uneven support. A structural engineer or geotechnical assessment identifies which cause is at work, which determines the right repair.
The warning signs
Subsidence typically shows as diagonal cracks wider than about 3mm, often near doors and windows and visible both inside and outside the same spot, sometimes with doors and windows sticking, rippling wallpaper, or sloping floors. New, widening, diagonal cracks are the concern; fine, stable, vertical cracks usually are not. See how to spot subsidence cracks.
What it means for selling
If your home has or has had subsidence, the cause and current status matter for selling. Historic, resolved subsidence (diagnosed, repaired, now stable, with documentation) is often still mortgageable; active subsidence usually limits you to cash buyers until fixed. Either way you must disclose it. A structural engineer’s report establishing the cause and status is the key document — and a cash buyer will purchase a subsidence-affected home as-is and complete in 7-28 days. See selling with subsidence.
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Written & reviewed by Lisa Hayes, Founder
Lisa Hayes is the founder of Ready Steady Sell and an independent UK home-selling expert with over a decade helping homeowners weigh cash house buyers, property investors and the wider fast house-sale industry — without pressure or hidden fees. Every guide is reviewed for accuracy under our editorial standards.
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Frequently asked questions
Straight answers, no sales talk
What causes subsidence?
The ground beneath a property sinking — most often from clay-soil shrinkage in dry weather, tree and shrub roots drawing moisture, leaking drains washing away soil, or ground conditions like old mine workings.
What is the most common cause of subsidence in the UK?
Shrinkable clay soil that loses moisture and shrinks in dry weather, often made worse by nearby trees and large shrubs whose roots draw water from the soil.
Can trees cause subsidence?
Yes — large trees and shrubs near a home draw moisture from clay soil, accelerating shrinkage and the ground movement that causes subsidence. Managing them can be part of the fix.
What are the signs of subsidence?
Diagonal cracks wider than about 3mm, often near doors and windows and visible inside and out, sometimes with sticking doors, rippling wallpaper or sloping floors.
How is the cause of subsidence found?
A structural engineer or geotechnical assessment identifies the cause — clay shrinkage, trees, leaking drains or ground conditions — which determines the right repair.
Can I sell a house with subsidence?
Yes. Historic, documented subsidence is often still mortgageable; active subsidence usually means cash buyers until fixed. You must disclose it, and a cash buyer buys as-is in 7-28 days.