There are many reasons why the foundations of a house may need to be strengthened through underpinning. Not all are due to subsidence, but that’s the most common cause. Underpinning can significantly improve your home if it’s carried out by experts, but it’s essential to follow the correct procedures.
Why Your House May Need Underpinning
The most common reason for underpinning a building is subsidence. You’re likely to be alerted to this by finding significant cracks in the walls, or especially around the door or window frames. This may have been caused by erosion or old mine workings, or the quality of the soil could be too poor to support the building.
On the other hand, you may need underpinning because you’ve made improvements, increasing the load on the foundations, or because you’re building an extension.
Making the Decision
It’s essential to get a professional opinion before you make any decisions from a surveyor or structural engineer, who’ll advise you on the action to take. It may be nothing more than having drains fixed or a tree root removed, but the building could well need to be underpinned.
The report will probably include a recommendation of what type of underpinning will be most effective. Of the two main approaches, the more traditional method is to excavate the foundations section by section and pour in concrete. This tends to be a long and disruptive process, but it’s sometimes the best option.
The alternative is piling, where piles are bored or driven through the weaker soil into stronger soil or bedrock, allowing the weight of the building to be transferred downwards. This is generally a quicker and less invasive method.
Things to Consider
You may be advised by friends or family to avoid underpinning, since it can make your house more expensive to insure. While this is true to some extent, more expensive insurance is better than a building reduced to rubble, which could happen if no action is taken. In any case, there are signs of the insurance industry waking up to the fact that an underpinned house is actually more secure, not less.
It’s vital to take care when choosing your contractor. While it’s always tempting to go for the cheapest quote, it’s much more important to ensure you pick a company that specialises in the underpinning method you’ve chosen, not a general builder offering it at a cut price.
If you have any questions about an underpinning project, feel free to get in touch with us.