Waterproofing materials

Since reliance has often to be placed on the waterproofing system, the designer must ensure that the materials are properly selected and adequate for the proposed location and conditions. It is imperative that all continuous horizontal, sloping or vertical waterproofing be specified, and executed, in one proprietary waterproofing system.

There is a wide range of products used for structural waterproofing. Most proprietary systems and materials are covered by British Standards, Agrément certificates or manufacturers’ and installers’ warranties. The typical range of barrier materials and cavity drain membranes is given in BS 8102.

Our guidance document Basements: Waterproofing separates them into seven distinct categories according to product type, form and application as follows:

  • Category 1: Bonded sheet membranes
  • Category 2: Cavity drain membranes
  • Category 3: Bentonite clay active membranes
  • Category 4: Liquid-applied membranes
  • Category 5: Mastic asphalt membranes
  • Category 6: Cementitious crystallisation active systems
  • Category 7: Proprietary cementitious multi-coat renders, toppings and coatings

Categories 1 and 3–7 are regarded as barrier materials for use as Type A protection (and may be combined with a Type B protection) whereas Category 2 is a membrane that creates a drainable cavity and is part of a Type C protection system.

Further information is available from our guidance document Basements: Waterproofing