QUICK GUIDE Types of waterproofing protection

There are three basic options for safeguarding a habitable basement against water ingress. Your designer or structural engineer should select the best system for your project, in tandem with advice from a waterproofing specialist.

Type A Often referred to as tanking, this involves adding a waterproof barrier to the basement structure. This could be applied externally to the walls and floor slab, but products are also available for internal use. The downside of relying solely on Type A protection is that any defects can be hard to pinpoint and resolve.

Type B This involves the use of structurally integral protection, which basically translates to using waterproof concrete to form the shell of the basement. Correct specification and careful construction is vital to success. The most common defects are due to poor mixes, bad workmanship, leaks at construction joints and cracking.

Type C Known as drained protection, this method uses the structure as an initial barrier – but assumes that some moisture will penetrate. A special membrane creates a cavity between wall/floor and the internal environment. Any water that seeps through is collected and redirected to a suitable discharge point (eg by pumping it to drains).