What is subsidence: A guide to causes, signs, and prevention tips

Published: 26/05/2026

As a landlord, you probably know that subsidence is something to be avoided at all costs due to expensive repairs and the danger it poses to tenants. But what is subsidence? What causes it? And how can you prevent it?

In this guide, our private rented sector experts outline the main causes and telltale signs of subsidence, and advise how to minimise the risks of it happening.

Check out our other resources on looking after your property effectively.

What is subsidence?

Subsidence is a process where the ground beneath your property sinks, taking its foundations with it. This can cause a shift in the structure of your walls or floors, potentially destabilising your property’s structure. Several events can lead to subsidence, including environmental factors, infrastructure failures, and the effects of nearby mining.

What causes subsidence?

When it comes to identifying what causes subsidence, there are a few likely offenders, including:

Clay shrinkage

After losing moisture in long, hot summers, clay-rich soil contracts and cracks, leading to movement in the ground above, potentially impacting building foundations.

Poor foundations

Shallow or weak foundations, often common in older buildings, can make them more susceptible to shifting. Other groundwork issues include using the wrong materials, poor ground preparation, or buildings constructed on 'made-up ground'.

Tree roots and vegetation

Tree roots can absorb up to 1,000 litres per day from soil, causing it to dry and contract. Any large trees nearby, particularly thirsty species like willow, poplar, and oak, could cause the ground to shift.

Climate

Frozen pipes due to extreme cold can burst, leading to underground leaks that wash away soil. Heavy rainfall followed by dry spells can cause the ground to expand and contract, and floods can wash away the soil beneath buildings.

Mining and underground voids

Excavation or mining work near a property can impact soil stability and weaken the ground.

Drain leaks

Leaking pipes or faulty drainage systems can soften or wash away the ground beneath a building.

What are the first signs of subsidence?

Detecting subsidence early can save you from costly repairs and keep your tenants safe in their home. But what does subsidence look like? The most common signs are:

Cracks in walls

Not all cracks are caused by something sinister, but some can indicate a deeper issue. So what do subsidence cracks look like? If your crack is wider than 3mm, can be seen from inside and outside, or is wider at the top than the bottom, then you should ask an expert to rule out subsidence as a cause.

Door and window misalignment

A shift in the property's height, or cracks forming near windows and doors, can mean they are no longer fitting as tightly as they used to – a common sign that subsidence may be an issue.

Uneven floors

Sloping or uneven floors can indicate that your property’s foundations are no longer straight and that it may be suffering from subsidence.

Ripples in wallpaper

If you spot ripples or creases in your wallpaper and can rule out condensation as a cause, it’s worth checking whether subsidence is to blame.

How to prevent subsidence

While it’s not always possible to avoid subsidence on your property, there are many things you can do to reduce the risk, including:

Don’t remove trees; regularly prune them instead. Ensure any new trees or shrubs are planted as far away as their mature height.
Maintaining gutters and plumbing to prevent soil erosion due to leaks. Check these systems once a year.
Ensuring builders follow regulations if undertaking structural work, or adding an extension.

↔ Scroll to see full table

Cause	Risk	Prevention
Clay shrinkage	Hot weather causes ground shrinkage	Maintain consistent moisture levels
Poor foundations	Shallow, weak, or poorly built foundations cause shifting	Remedy any fixable issue, consider underpinning as last resort
Tree roots and vegetation	Roots absorb moisture that weakens the surrounding ground	Prune trees and shrubs regularly, plant new trees at suitable distance
Climate	Pipes freeze, rainfall causes drain swell, floods washing away soil	Lag pipes, don't remove large trees that soak up ground water
Mining and underground voids	Nearby cavities cause collapse or movement	Conduct surveys before building, monitor structural integrity
Drain leaks	Soil erosion, leading to sinkage	Maintain drains, plumbing and guttering systems

How to fix subsidence

As soon as you suspect your property may be suffering from subsidence, it’s important to contact your insurer, who will advise what to do next. But how do you fix subsidence?

First up, a chartered surveyor will be needed to assess the issue and its root cause. They may suggest a number of options, including:

Monitoring the situation in case the issue naturally improves.
The better management of trees near the property.
Improving nearby drainage or fixing plumbing or guttering issues.
Underpinning – an expensive process that involves strengthening the property’s existing foundations

What are the risks of subsidence?

Because the causes of subsidence tend to develop slowly, it can be easy to put repairs off. But what happens if a house has subsidence? Risks range from devaluation to possible collapse, and include finding it harder to sell, paying higher insurance premiums, and, worse still, endangering your tenants.

Can you let a property with a history of subsidence?

The short answer is yes, there is no legal reason why you can’t. However, some tenants may be unwilling to live in a property that has previously had subsidence issues. Be prepared to provide evidence that the property is safe to live in, such as proof of any repair works or surveys you’ve had done.

How we can help you

Worrying about what to do about subsidence? You don’t have to worry alone. Our members have access to a suite of resources and guides, licensing support, and specialist telephone advice from our private rented sector experts.

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Subsidence FAQs

How do I check if my house has subsidence?

You can look for signs yourself, such as cracks wider than 3mm, uneven floors, doors or windows, and ripples in the wallpaper, or, if you are concerned you may have subsidence, you can book a professional structural survey.

Does landlord insurance cover subsidence?

A comprehensive landlord insurance policy, such as one through our insurance partners, should cover all of the costs to repair a building affected by subsidence. Always check your policy document.

Can subsidence cause a house to collapse?

Subsidence can cause severe structural damage and eventually collapse, so it’s vital not to ignore any warning signs and to fix issues promptly.

What is heave?

Heave occurs when the ground rises, often due to excess moisture in the soil, pushing the foundations upward.

What is landslip?

Landslip is often caused by soil erosion or by building near a slope, and occurs when the ground beneath a property moves sideways, causing the foundation to shift horizontally.

Do I need to declare subsidence?

If you're selling, you legally need to inform your estate agent and buyer about any current or previous subsidence issues at the property. You must always declare subsidence to your insurance company to avoid nullifying any future claims.

How much does it cost to fix subsidence?

The cost of fixing subsidence varies from claim to claim. The average cost of underpinning sits around £12,500, though repair costs can reach significantly higher, and even stretch into the hundreds of thousands.

Are subsidence and settlement the same?

No. Settlement, also known as ‘compaction’, refers to the sinking of new properties under the weight of the building, and usually stabilises in 5-10 years.