Written by, Marija Petkova
Updated April, 17, 2022
Did you know that there is more than just the foundation under a house?
In fact, several structural elements work together to create a stable base for your home.
If you wonder what is underpinning a house, when is it necessary, and how much it costs, keep reading to find out!
Underpinning is the process of strengthening and stabilising the foundation of an existing building to prevent it from collapsing in the future.
Typically, owners underpin their house or other properties when the original foundations are no longer strong enough to support the weight of the building or when the ground around the base has changed either through subsidence (land sinking) or water table shifting.
Vendors are required by law to reveal if a property has previously been underpinned, especially if they are flipping houses. Even if they do not, a structural survey should reveal that fact.
Underpinning a house is time-consuming, expensive, and challenging work that results in an extended underpinned property longer by several metres and skewered into the ground.
Depending on the extent of the subsidence and structural problems, the process to underpin a house may include one or more of the following approaches:
Note: The most effective and expensive method is not always necessary, and your construction specialist will be able to advise you on the best course of action for your particular needs.
Underpinning a house is necessary when the existing foundation is in poor condition or the soil becomes unstable and begins sinking (subsidence) due to factors such as:
Other reasons for needing underpinning include:
Underpinning is not always necessary. If the soil sinkage is minor and has been caused by factors like drought, you may be able to correct the problem by watering the ground.
Also, if the cost of underpinning is greater than what it takes to repair or replace the existing foundation, you shouldn’t waste money on underpinning procedures.
To underpin your house, you would have to pay anywhere between £1,000 to £20,000 as the prices vary depending on the property’s size and condition, as well as the type of underpinning required.
Moreover, there may be additional and unsuspected costs for services like replacing bricks and timbers damaged by subsidence, as well as interior decoration expenses to repair wall, windows, doors, and floor damage.
Note: If you have recently purchased an underpinned house with hidden flaws, or it has been damaged due to the lack of underpinning, your seller may be liable for the damages you may have incurred.
In most cases, house underpinning is not covered by standard home insurance policies, as it is considered to be a preventative measure rather than a repair.
However, you can obtain a specialist home underpinning insurance in the UK that covers the costs to underpin your house and mend any damages it has sustained.
Note: If you plan on extending your property or want to make some structural modifications unrelated to underpinning, then this kind of work won’t be covered by your insurance.
While costly, underpinning your property is crucial to repairing existing damage to your house and its foundation or preventing future destruction caused by anything from subsidence to house extensions. That way, you’ll keep your home safe and sound for years to come.
Depending on the degree of the subsidence and the damages it has caused, a property that has been underpinned might be worth 20% to 25% less.
The cost to underpin your house varies between £1,000 and £20,000 depending on factors such as the size of your property and the type of underpinning you require.
If you’re buying an underpinned house, there shouldn’t be any problems with your mortgage or your insurance as long as the property’s structure shows no further issues.
House underpinning is a construction technique used to strengthen the foundation of a house or add another foundation layer below the existing one.