Can you get buildings insurance on underpinned houses?

Key takeaways

• Underpinning is a way of strengthening a house’s foundations. Techniques include soil strengthening, concrete bases, installing beams, and screw piles with brackets.

• Properties are usually underpinned due to subsidence.

• The cost of underpinning ranges from £5,000 to £25,000, depending on property size*

• Buildings insurance for underpinned homes is available but may come with higher premiums

If your home has suffered from subsidence, it’s likely you’ve had it ‘underpinned’ to secure its foundations.  

You can get buildings insurance for underpinned houses. However, you might find that your premiums are higher than average. Make sure you compare policies, so you can find the best deal for you. 

What is underpinning? 

Underpinning is a construction process that provides stabilisation to the foundations of an existing building.

This is typically done when the foundation is not strong enough to support the structure, often due to subsidence or other soil-related issues.

What does underpinning involve? 

The underpinning process involves reinforcing or strengthening the foundations of a house or other building. This is typically done by extending the depth and/or breadth of the foundation, often in stages, to provide more stable support.

There are several types of underpinning. The four most common methods are:

The method of underpinning used will depend on what your property’s exact issues are.

Why is underpinning necessary? 

Underpinning work is necessary to strengthen and stabilize building foundations of an existing structure, usually when they have been compromised by subsidence.

Subsidence is when the ground below your home sinks. This might be caused by trees sapping excess water from the ground around your home, droughts, or if leaks under your home are affecting the soil structure.

Other reasons underpinning might be necessary include:

• Inadequate foundations

• Poor soil conditions or ground conditions

• Excavation

• Adding a loft conversion or basement, which increases the load on the bearing capacity of the foundations

How much does underpinning cost? 

The average cost of underpinning in the UK is £13,500, according to MyJobQuote (1)

The cost of underpinning your home will depend on how big the property. Some trade websites offer quotes per square meter or foot, so you’ll be able to work it out roughly based on the size of your home. 

Should I buy an underpinned property? 

You should get a survey done and check the cost of insurance before buying an underpinned property.

A house being underpinned can be an indication of past or ongoing issues with the house’s foundations and structure.

If you’re looking at homes and find one you like that’s been underpinned, get a full structural survey done to find out if underpinning has resolved the problem or whether more work might be required.

Underpinned properties, and those with a history of subsidence, can cost more to insure.

Bear in mind that it might be difficult to sell a home with underpinned foundations for the same reasons.  

Buying a house requiring underpinning - with the work yet to be done - is another matter entirely. Mortgage companies are unlikely to offer a loan on a property with ongoing or untreated subsidence.

What are the signs of subsidence? 

There are several visible signs of subsidence to look out for inside and outside the house - the main one is cracks in your walls.

Cracks can occur for various reasons but signs of subsidence include:

• A crack more than 3mm thick

• A diagonally positioned crack that is wider at the top and slimmer at the bottom 

• A crack that can be seen both internally and externally

• A crack near a door or window

• A crack which has spread under the damp-proof course

• Cracks where an extension joins the house

Other signs of subsidence are:

• Wallpaper creasing at the joins where the wall meets the ceiling 

• Doors and windows sticking

• Floors starting to drop to one side of a room

However, not all cracks or structural movements indicate subsidence. Cracks can sometimes occur in new build homes as they settle into their foundations, or in any buildings as a result of expansion and contraction caused by hot and cold weather.   

When you get a survey done, the surveyor will be able to give you an indication of whether they suspect subsidence.

You will then need to arrange for a structural engineer to visit the property to get a definitive answer. The engineer will produce an in-depth report that will tell you the extent of any subsidence, what repairs are required and how much they will cost.

Emma Lunn
Personal finance expert

Our expert says

Subsidence is a word most homeowners dread because the damage it causes can be expensive but if you do spot any signs of it, it’s important to act quickly. The longer you leave it, the worse it will get and getting the problem fixed early can save you a lot of money down the line.

Your home insurance should cover you for a subsidence claim but if you’re unsure, check the policy document so you know exactly what you’re covered for and how much excess you can be expected to pay.

What increases the risk of subsidence? 

Homes will be at a greater risk of subsidence if: 

• They are surrounded by trees that dry the soil out and cause it to erode 

• They are built on clay soil that can dry out and shrink in warm weather 

• They are prone to waterlogged soil as a result of poor drainage or flooding 

Do you have to declare subsidence when buying buildings insurance? 

Yes, you will need to declare subsidence when you buy buildings insurance. You’ll need to include details of when it occurred, what caused it, and how underpinning was carried out to resolve the issue.

You’ll need to show that your property is no longer having subsidence issues before you’re able to get cover.  

You’ll usually need to pay more for cover if your home has been underpinned or has had subsidence issues previously - and you might need to pay a higher excess on claims.

In some cases you may have to take out non-standard home insurance to ensure you’re adequately covered. 

Can you get a mortgage on an underpinned house? 

Some lenders might not be as keen to offer a mortgage for an underpinned house, but if surveys show there are no longer any issues you should be able to get a mortgage.

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*Resource: Underpinning Cost Guide 2025: How Much For Underpinning?