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Can you get buildings insurance on underpinned houses?

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Written by  Mehdi Punjwani
5 min read
Updated: 07 Feb 2024

If you’ve had your home underpinned to resolve an issue with subsidence you may be wondering how this can affect your buildings insurance policy and premiums. Read on for everything you need to know.

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 as many insurers offer policies for underpinned properties. However, you might find that your premiums are slightly higher than standard as a result - which makes it so important to compare policies, so you can find the best deal for you. 

What is underpinning? 

Underpinning is what you can have done to your house in order to increase the strength of its foundations. It’s often required when a house is affected by subsidence - or when the ground underneath the house is moving or sinking.  

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What does underpinning entail? 

When your house is underpinned, it means one of a few types of construction techniques is used to strengthen its foundations. The four most common ways that this is carried out include: 

  1. Strengthening the soil: This is done with a geopolymer resin that’s injected into the ground surrounding the foundations to replace and fortify the eroded soil 

  2. Providing a concrete base: This is when the ground below the foundations is dug out and replaced with concrete to support the foundations themselves 

  3. Installing beams: Concrete beams are set below the existing foundations to allow for better weight distribution  

  4. Screw piles and brackets: Screw piles are steel shafts, which are filled with concrete or grout before being inserted into the ground for supporting brackets to anchor on, and create a more level foundation  

Why is underpinning necessary? 

Houses are generally underpinned in response to subsidence issues, where the building is sinking into its foundations. Often a last resort, underpinning can be expensive and time-consuming - and is often done when other methods don’t work. 

For example, sometimes subsidence is caused by trees sapping excess water from the ground around your home, or if leaks under your home are affecting the soil structure, then addressing these issues would ideally take care of the issue. If not, then underpinning is generally the only option left. 

Underpinning also might be required if there is no subsidence issue, but if for any other reason it’s decided that your home’s foundations aren’t strong enough - perhaps if you’re adding an extra floor to your home.  

How much does underpinning cost? 

The cost of underpinning your home will depend on how big the property is, but costs can range from £5,000 to £25,000. 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? 

A house being underpinned isn’t necessarily a dealbreaker in itself, but it 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, carrying out a full structural survey is key to finding out what kind of shape the property is in and whether there are any unresolved issues. 

Also factor in that it might present a challenge trying to sell a home with underpinned foundations for the same reasons, so it’s advisable to be careful and thorough before making any decisions.  

How do I check for subsidence? 

The biggest tell-tale sign of subsidence in your home will be the appearance of cracks in your walls - but this isn’t a cause for concern on its own. 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.   To assess whether cracks in your walls are caused by subsidence, take note if:  

  • The gap is wider than 2mm along the whole length of the crack, or wider than 5mm along any part of the crack 

  • The crack runs diagonally 

  • The crack is wider at one end than the other 

  • The crack can be seen on both inner and outer walls 

  • The crack is growing 

  • Cracks appear around doors or windows 

 Aside from cracks in the walls, other symptoms of house subsidence include uneven floors and ceilings, gaps between the floors and walls, and doors and windows being harder to open. 

Rebecca Goodman
Rebecca Goodman
Financial journalist

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? 

Some 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 getting buildings insurance? 

Yes, you will need to declare subsidence, including 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.  

It’s likely you’ll need to pay more for cover if your home has been underpinned or has had subsidence issues previously - and you might even need to pay a higher excess fee for 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 generally speaking if surveys show there are no longer any issues you shouldn’t have too much trouble.