Home insurance: subsidence

What is subsidence?

Subsidence occurs when the foundation of your house collapses or sinks.

This is often caused by:

• soil, usually clay, shrinking and swelling because of the weather
• nearby trees and shrubs absorbing the moisture in the soil beneath your home
• leaking drains softening the ground under your home.

It can have consequences for the value of your property and can greatly increase the cost of your home insurance.

Here, we explain how to spot, prevent and insure for subsidence.

• Find out more: the best and worst home insurers

What are the signs of subsidence?

Your property might be subsiding if you spot any of the following signs:

• sudden cracks in plaster and brickwork that are wider at the top than at the bottom
• doors and windows sticking for no reason
• rippling wallpaper that isn't caused by damp.

It's important to note that cracks can appear on walls for varying reasons, so spotting one might not be a cause for panic. Settlement – where a building settles under its own weight – can also cause cracks to appear on walls. This is often seen in newly built homes and extensions.

If a crack is caused by subsidence it will be:

• more than 3mm thick – often getting wider over time
• diagonal
• wider at the top than at the bottom
• visible from inside and outside your home
• close to doors and windows.

Is subsidence covered by home insurance?

Most home insurers cover subsidence damage as standard, albeit normally with an excess of £1,000.

Of the 76 buildings policies we examined, only one buildings policy potentially applies a lower subsidence excess. With Lemonade, it's £950.

Most buildings insurance policies will cover subsidence to your house, but many won't cover adjoining areas such as patios, garden walls, driveways and swimming pools unless the main residence is also affected.

Subsidence cover is standard in most policies, but if your property has been previously affected you may find it more difficult to find insurers that will accept you as a customer.

If you can't find an insurer that will cover you on affordable terms, it may be worth trying a specialist broker.

The British Insurance Brokers' Association can provide further practical advice and can recommend a specialist if you suspect your property has subsidence.

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Is my home at risk of subsidence?

Factors that can affect your risk of subsidence include:

Clay soil

Properties built on clay soil are at great risk of experiencing subsidence. Clay soil can shrink, crack and shift during hot, dry weather, making the ground unstable and potentially causing the foundations of your property to sink.

Drought

Homes in drought-prone areas are particularly at risk of subsidence because the soil is much more likely to dry out.

Trees and shrubs

Trees and shrubs around your home can increase your risk of subsidence. Some species absorb a lot of water, which makes the soil much drier.

Old homes

Subsidence is more common in Victorian and Edwardian houses as their foundations are shallower than the current UK minimum of one metre. This makes them more susceptible to damage from any movements in the ground.

Leaking drains

Leaking drains and water mains can increase your risk of subsidence as they wash away or soften soil, causing it to compact under the weight of your property over time.

Underpinning

Properties that have had their foundations underpinned may have experienced subsidence previously and are therefore at a greater risk.

Can I reduce my risk of subsidence?

You can reduce your risk of subsidence by taking the following steps:

• Plant trees and shrubs at least 5-10 metres away from your property.
• Prune the branches on your trees regularly.
• Keep pipes and drainage systems well maintained to stop water from leaking into the soil beneath your house.
• Check the surveyor's report for signs of subsidence before buying a new home.

We've put together a guide to the house surveys you can get when buying, including estimated costs, a sample report and the accreditations to look for.

• Find out more: best buildings insurance

Subsidence: your questions answered