Underpinning a House

Underpinning a House

Has someone mentioned underpinning a house before or that your house in particular needs underpinning? The suggestion strikes fear in many people. Part of that is because it can be an expensive process, but there are also many misunderstandings about underpinning and what it means for a building.

What Is Underpinning?

Though the word underpinning is more often used in a figurative sense, it actually means adding to the foundations of a building in order to strengthen them. This may be because the original foundations are inadequate, which was quite common in older buildings.

Most commonly, however, the reason for underpinning a house is that it’s suffered subsidence. This may be because the ground beneath the building is weak or has become waterlogged. Alternatively, there may be excavations, such as old mine-workings, underneath.

Not all cases of subsidence require underpinning. For instance, the ground may have become waterlogged because of a fault in the drains, and fixing the drains could be enough. However, if the situation is permanent, there might be no alternative to strengthening the foundations.

How Is Underpinning a House or building Carried Out?

Broadly, there are two methods of underpinning a building — traditional underpinning and piling.

The traditional method, also known as mass concrete underpinning, involves excavating beneath the foundations, section by section, and filling the cavities with concrete. This is a longwinded process that’s far less common than it used to be, but it’s still an option where alternatives are unsuitable.

Piling, on the other hand, has grown in popularity, especially since the introduction of minipiling, which makes the process easier in a confined space. Essentially, piling involves either driving or boring below the foundations and inserting piles that rest on either stronger earth or the bedrock. This transfers the weight of the building down to a solid support.

What’s the Cost of Underpinning?

Most immediate, underpinning is an expensive process. Typically, underpinning an average-sized house is likely to cost between £10,000 and £15,000, although it may be more if the subsidence has made structural repairs necessary. However, it’s quite possible your building insurance policy will cover this, so you won’t have to pay out that amount.

A more long-term cost is that an underpinned house is often more difficult and more expensive to insure. This is because of insurers’ often baseless assumption that the problem is likely to recur. However, some insurers specialise in underpinned buildings or have dedicated underpinning teams. As long as you can provide evidence that your house is now secure, it should be possible to arrange insurance.

The more relevant question, though, is what it’s likely to cost you not to have underpinning done — and that could be losing your home. You can find out more about underpinning a house by getting in touch with us for a chat.


Here’s an article you might find interesting: Does It Affect Your Insurance if Your House Is Underpinned?