CM20 Membrane

CM20 High Capacity Waterproofing Membrane is for use on walls, floors, vaults and tunnels with minimal surface preparation required. 


  • Part of a Type C Cavity Drain Membrane System, in line with BS8102:2009

  • Gives a high water void at a volume of 14 Litres/m²

  • Quick to install – easy to roll out along floors

  • Creates a dry, habitable living space in areas previously suffering from damp/wet conditions

  • Easily cut down using a sharp blade

  • Waterproof, salt inhibiting, root and contaminant resistant

  • Little or no damage to the existing structure

  • Low and high temperature tolerance

  • High grade material

  • Available in rolls of 2 m x 20 m and 2 m x 10 m* (*only 22kg in weight for safe manual handling)

CM20 Waterproofing Membrane is BBA-approved as suitable for type ‘C’ Cavity Drain Membrane Systems in accordance with BS8102 and now includes our high-vis yellow membrane.

This waterproofing membrane is the highest drainage capacity membrane in the CM range, giving a void of 14 litres/m². Suitable for use on floors and walls in very wet situations, or where a large stud height is needed to maximise insulation values.

This membrane is available in 2m width as 20m rolls or 10m rolls, the latter being light enough for individual manual handling.

CM20 creates a dry, habitable living space in areas previously suffering from damp or wet conditions.

Additional CM8 Mesh key information can be viewed in the PDF below: