Design requirements for keeping your basement dry

With space at an ever increasing premium it is no surprise that basements are becoming more popular with self-builders and developers alike. However, the UK remains way behind other countries. In fact it is estimated that only 2% of new homes in the UK have basements, compared to 30% in the USA and a whopping 80% in Germany. With one of the wettest climates in Europe, how do we ensure these basements stay dry?

What is a basement?

Whilst this may seem straight forward, sloping sites can make understanding what is considered a basement more difficult. This can be seen in the fact that although only 2% of homes use completely submerged basements, around 7% make the most of sloping sites with partially submerged rooms.

We would consider a room to be a basement where any floor becomes below the ground level on one or more levels. So, if your lower level is built into a hillside, meaning part of it is below the ground level of the above floor, this would be a basement.

What do we require?

If you’re building or converting a basement, LABC Warranty require you to engage the services of a waterproofing specialist as part of your design team. We would consider a credible waterproofing specialist to be a “Certificated Surveyor in Structural Waterproofing (CSSW) or equivalent.” The design specialist should be responsible for designing an integrated waterproofing solution to eliminate the risk of water ingress.

Why is this required?

Unfortunately, the UK climate means that water ingress is a real risk for any underground structure. This is a specialist area; we require the use of a specialist to limit the risk of damp penetration and make sure people can enjoy the home for years to come.

Further details and guidance can be found in Chapter 6 of our Technical Manual.


By Craig Ross

Please Note: Every care was taken to ensure the information in this article was correct at the time of publication. However, for the most up to date LABC Warranty technical guidance please refer to your Risk Management Surveyor and the latest version of the LABC Warranty technical manual.