U&M Group

Guidelines for Underpinning Your Basement

Friday, November 30th, 2018 AT 10:28AM

There are many excellent reasons for adding a basement to your home, from creating an independent flat to having an indoor swimming pool. It’s a major job, though, and one of the most important aspects is ensuring the foundations of your house remain strong. This means underpinning to form the basement.

Why Have a Basement?

Growing families eventually outgrow their homes, and one option is to move to a bigger place. That’s not only a huge upheaval, though — it’s also prohibitively expensive for many people at current house prices.

An increasingly popular alternative is to add a basement to the existing house. This could be used as an extra bedroom or living room, or else as a playroom for the kids or a games room for the whole family. It could even be converted into a flat, perhaps for an older teenager.

Why Would Your Basement Need Underpinning?

If you’re having space under your home excavated for a basement, this means digging under its existing foundations, leaving the whole structure at risk. Underpinning will replace the lost foundations and restore the building to full strength.

There are various approaches to underpinning, but the most likely methods to be used when constructing your basement are either mass concrete underpinning and/or mini piles. The method adopted is chosen for a variety of factors: ground conditions, groundwater, access and proximity to other structures to name a few. The ultimate aim is to transfer the load from the existing structure to the proposed basement level while providing a retaining structure for the ground surrounding the basement.

What Needs to Be Done?

The process of underpinning is an integral part of creating a new basement. It’s therefore preferable to employ a contractor that specialises in both underpinning and constructing basements. The things you’ll need to do include:

  • A professional survey of the site, especially the state of the soil, which will help to determine which kind of underpinning should be used.
  • Check the contractor’s record and specialisation before hiring — it’s important not to hire a general builder with no record of underpinning.
  • Check with your local authority whether you need planning permission.
  • Find out if the work will affect any party wall agreement.
  • Plan ahead for how you’ll deal with the disruption while the work is being carried out.
  • Make sure the contractor you hire will fully clear up and restore the site when the job is over.

Feel free to get in touch with us if you want to know more about underpinning your basement.