Wykamol CM20 Cavity Drain Membrane

Product code CM20-20
  • RRP £115.50
  • £138.60
  • £115.50
(47 items in stock)

Wykamol CM20 drainage membrane has been developed for use in waterproofing basement and cellar floors.  It is manufactured in the UK from high-density polyethylene (HDPE) and is impermeable to water, water vapour and radon gas. The product provides an effective barrier to the transmission of salts or other contaminants from the substrate

The deep 20mm stand-off studs ensure this flooring membrane offers high-drainage capacity as part of a cavity drain tanking system with provision made for disposing of water build-up behind the membrane. Floors beneath the membrane should have a drainage outlet point. There should be a fall towards the outlet point or a drainage channel made around the perimeter of the floor, to ensure that water can flow to the outlet or to a pump and sump.

CM20 cavity drain membrane is satisfactory for use in Type C (drained protection) constructions in accordance with BS 8102 : 2009.  The product is is BBA approved and is suitable for use In accordance with NBS Specification J40 (clause 290) – Flexible Sheet Tanking / Damp Proofing.­ 

Roll sizes: 20m2 (2m x 10m) and 40m2 (2m x 20m).

  Wykamol CM20   Data
  Material   HDPE
  Sheet Thickness   1mm
  Membrane Height   20mm
  Water Void Capacity   >14.61 l//m²
  Weight   1 Kg/m² 
  Water tightness at 60 kPa   >24 hours
  Working Temperature   -50°C to +80°C
  Softening Temperature   126°C
  Mean Compressive Strength   165 kN/m² 


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