What's subsidence and what causes it?

Subsidence puts stress on the structure of your home which can result in cracks, depending on the severity. Here are a few common causes of subsidence: The soil your home is built on shrinks in dry weather, so your home could sink slightly, making it lopsided and causing major cracks in wallls Homes built on clay soil will be affected more than those that aren’t, as clay soil shrinks a lot when the weather is warm Tree roots and leaking drains dislodging the soil beneath your home can cause subsidence Homes built in an area that used to be mined can have unstable foundations, which can lead to subsidence too .

Ground heave is the opposite of subsidence. It’s the upward movement of the ground when soil gets wet and expands

What if my house has had subsidence before?

To work out whether subsidence has been an issue for your house, check the subsidence history of the property. You could ask your neighbours about the area. Properties with a history of subsidence are difficult to insure and you might end up paying higher premiums with a specialist insurer - shop around to find a policy that works for you.

When subsidence is caused by coastal or river bank erosion, insurers might reject a claim if they exclude these causes. And, if there’s a solitary occurrence of loss or damage to swimming pools, hot tubs, tennis courts, drives, patios, walls, fences and gates, because of subsidence they probably won’t be covered. However, if the subsidence happens simultaneously to your house and outdoor areas, you can probably make a claim. Speak to your insurer about the specifics of your policy.

How to spot subsidence

Most homes will get a crack or two, but cracks from subsidence look slightly different. Subsidence cracks can appear and spread quickly, be thinner at one end, run diagonally, be found on the inside and outside of the building and around windows and doors. Other signs of subsidence include: Doors and windows not closing properly as they’re out of alignment Wallpaper wrinkling along wall and ceiling joints Cracks where an extension joins your home

Subsidence insurance

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What is subsidence?

Subsidence occurs when the ground beneath a building begins to sink.

The sinking causes stress on the foundations, resulting in cracks on the inside or outside of the building.

If left untreated, subsidence can cause the building to lean to one side and become structurally unsound.

It can cost a lot to repair damage caused by subsidence, so it's worth making sure your home insurance covers it.

What does subsidence insurance cover?

Most buildings insurance policies will cover subsidence, but only if your home has never suffered from the problem in the past.

A standard subsidence home policy would likely cover:

Repairs to damages
Replacement costs for lost items
Alternative accommodation

If your home has irregular features or is at risk of coastal or river bank erosion, you’ll likely need to pursue specialist insurance.

You may also need specialist cover for damages to things outside of your home, underpinning and other subsidence preventative measures.

How much does subsidence insurance cost?

Between 1 November-30 November 2019 the average cost of home insurance policies with subsidence cover purchased through GoCompare was £276.26 a year^*.

The cost of subsidence insurance will vary depending on:

The type of property you own
How close trees are to your house
Your proximity to water

If you're looking to insure a property with a history of subsidence, it's probable that your premium will be higher than that of an equivalent building without a history of such problems.

If you're looking to renew your home insurance after a subsidence claim, your existing insurer may still offer you a renewal, but they're not obliged to and you're likely to see a rise in your premium.

Subsidence damage can be expensive to fix

Make sure you’re not stuck with the bill by finding the right subsidence insurance

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What causes subsidence?

Here are a few common causes of subsidence:

Trees and vegetation

Tree roots may disturb and dislodge the soil beneath your home causing subsidence.

The following trees are often involved in subsidence incidents:

Oak
Willow
Sycamore
Ash
Plane
Poplar

Clay soil

Homes built on clay soil will be affected more than those that aren’t, as clay soil shrinks a lot when the weather is warm. This is sometimes worsened by other factors such as trees.

Heat and drought

The soil your home is built on shrinks in dry weather, so your home could sink slightly, making it lopsided and causing major cracks in walls

Leaking water

Escape of water beneath a property could soften the underlying soil. This reduces the ground’s ability to support the weight of the building, causing it to sink.

Age and construction of property

Cracks and movement in old houses are due to the more traditional building materials that were used, such as lime, which allow the building to move more.

Poorly thought out renovations can also affect the structure, which makes subsidence more likely.

Underground mines

Homes built in an area that used to be mined can have unstable foundations, which can lead to subsidence too.

How can I avoid subsidence?

Here are a few ways you can prevent subsidence:

1. Don’t plant trees or shrubs too close to property

If you're planting new trees and shrubs, don’t put them too close to your home.

Buildings with shallow foundations are at risk of subsidence caused by trees and roots. If your house was built before 1950s, it will be particularly susceptible.

Tree roots seek water and grow towards drains which aren’t watertight. However, they’re unlikely to break through solid foundations.

2. Prune plants already there

Prune bushes and trees regularly. Have large, older trees surveyed every few years to see if they pose any immediate danger to your property.

3. Maintain underground pipes

If a pipe leaks or a drain overflows under your home, it will make the earth damp and weak, potentially causing heave and moving the foundations of your home.

You must maintain the pipes and drains under your home, even if they are difficult to access. If you suspect water’s escaped underneath your house, contact your insurer - it might put you in touch with a CCTV drainage surveyor.

4. Check for cracks and signs of subsidence

If you’re buying a house, look out for large diagonal cracks, inside and out, and check that the doors and windows shut properly.

If you can’t see any cosmetic concerns, read your homebuyers or RICS Building survey.

The latter is best for older properties because it breaks down structural issues into a traffic light, colour coded (red, amber, green) rating system, alerting you to any hidden structural red flags, not just for subsidence, and how serious the issue is.

The Homebuyer report doesn’t consider damage under floorboards or behind walls.

How to check for signs of subsidence

If you suspect your property is at risk, there are tell-tale signs that can help you identify whether you’re affected

Some of the signs are:

1. Large cracks

Cracks caused by subsidence may be found in inner and outer walls. They can appear and spread quickly, be thinner at one end, run diagonally, and be found around windows and doors.

2. Doors and windows not closing or opening

Doors and windows may become jammed, stuck or not close properly if they're out of alignment.

3. Sloping floors

Sagging or sloping floors, ceilings and walls may be an indication that your house foundations aren't straight.

4. Wallpaper wrinkling along wall and ceiling joints

Cracks in walls that are hidden beneath the wallpaper may cause it to wrinkle.

5. Cracks around a home extension

If you have an extension, you may spot cracks around where the extension joins your home.

Frequently asked questions

Can I get insurance if my property previously had subsidence?

To work out whether subsidence has been an issue for your house, check the subsidence history of the property. You could ask your neighbours about the area.
Properties with a history of subsidence are difficult to insure and you might end up paying higher premiums with a specialist insurer - shop around to find a policy that works for you.
What's the difference between subsidence and heave?

Ground heave is the opposite of subsidence. It’s the upward movement of the ground when soil gets wet and expands.
What is the subsidence excess?

Subsidence excess may cost more than the standard home insurance policy excess.
Repairing damages caused by subsidence can be expensive so insurers set a higher excess to try and recover some of the cost.
Look out for larger compulsory excesses if you need to claim. If there is an increased excess for subsidence, it’ll be listed in your policy documents.
Are cracks in a wall a sign of subsidence?

Most homes will get a crack or two, but cracks from subsidence look slightly different. Look for long cracks that run diagonally and are thinner at one end.