Underpinning the foundations on a building is a major operation, and the way it’s carried out can have a crucial effect on the building’s future. There are many pitfalls to the process — though fortunately most can be avoided by using expert professionals. Here are the main things to remember.
Get Your Building Professionally Surveyed
The worst thing you can do is dive straight into underpinning. If you see signs that may suggest subsidence, the first step should be to hire a Chartered Surveyor or Structural Engineer to look at the property.
Not all subsidence requires underpinning. Sometimes, it’s as simple as removing a tree whose roots are interfering with the foundations, or getting the drains fixed. The survey will tell you exactly what’s required.
Select the Appropriate Type of Underpinning
Each underpinning technique is the right one in specific circumstances. If you don’t need to excavate far down, traditional mass concrete underpinning may be fine. However, if the survey reveals that the sub-soil is poor to a depth of two metres or more, or that there’s a high water table, you’ll almost certainly need piling.
There are many kinds of piles and piling machines, and the best choice will reflect not only the condition of the ground but also issues such as access and the amount of headroom available. Both the Structural Engineer and the contractor you employ will be able to advise you on this.
Check Out the Legal Aspects
You shouldn’t start any building work without checking whether you need permission. The work may be notifiable under the Building Regulations, and you should also investigate if another building is close enough for the Party Wall Act 1996 to be relevant.
Again, any competent professional can advise you on these points, but it’s your responsibility to make sure you ask the right questions.
Choose the Right Contractor
Underpinning is a job for specialist professionals, not DIYers or a general builder, and your choice of contractor can make the difference between success and a botched job. With a major project, it’s natural to look for ways to keep down the cost, but that can mean going for the cheapest quote, instead of the one offering the best job.
It’s crucial to ensure the firm you choose has substantial specialist experience of underpinning. This will not only mean they have the necessary expertise, but also that they have the equipment required.
Feel free to get in touch with us for any advice or information you might need about your underpinning requirements.