Greengates Builders Merchants

Baseline 8 Membrane Kit



General purpose cavity drainage membrane for the isolation of damp/wet walls above and below ground.


Kontract 8 is a high density polyethylene membrane incorporating 8 mm studs which allow the creation of a

continuous drainage pathway for water in basement floors and walls and/or the isolation of damp walls above ground level.

The dry surface created allows rapid project completion via dry lining and screeding or timber floor finishes.


Kontract 8 has the following properties:

  • Stud height 8 mm, drainage volume 5.5 litres/m2
  • Sheet thickness 500 _m, density 0.5 kg/m2
  • Excellent low and high temperature stability
  • 120 kN/m2 load bearing capacity
  • High durability and water resistance



Kontract 8 is suitable for use in accordance with BS 8102:1990 to provide Type ā€˜Cā€™ drained protection to structures below ground giving a Grade 3 or 4 dry environment suitable for domestic or commercial use.

It is essential that Kontract 8 is used in conjunction with a suitable sump and pump facility (unless passive drainage is available on one side of the building) and that this is maintained throughout the lifetime of the installation. To control the risk of condensation it is recommended that all basements should be provided with mechanical ventilation to ensure adequate air circulation in accordance with the guidelines in Approved Document F (Building Regulations 2005).



Wykamol membranes provide a gas barrier system by the creation of an air gap when the studs of the membrane form a cavity within the building which allows the gas to flow freely beneath them to an extraction point. When dealing with gas situations it is imperative for all joints to be sealed with care. The installation of a specially calibrated positive pressure pump is needed to exhaust any gas that is contained behind the membrane.

Where a gas tight membrane is required which also forms part of the waterproofing system an additional sump system complete with an AMA Drainer 301 pump is required to remove water ingress collected by the system.

It is advised expert consultation and advice is sought when dealing with gas contamination issues.


Kontract 8 cavity drainage membrane can provide a dry, warm and habitable living space in basements and other areas suffering chronic damp conditions. However, it is equally important to ensure that areas which lack natural ventilation are provided with adequate means of condensation control, especially in wet areas such as kitchens, bathrooms etc. This is normally best dealt with through the provision of an effective

mechanical ventilation system.


Kontract 8 is normally finished by dry lining. Timber battens can be fixed to the wall via the pre-drilled screw threads in the Brick Plugs or plasterboard can be fixed to a timber or metal free-standing frame.

After fixing plasterboard and applying a suitable finish plaster permanent decorations such as vinyl papers or oil paints can be applied without delay.


For more information why not call in to our yard and speak to our staff or pick up an information leaflet.




Greengates Builders Merchants delivering to the whole of Lancashire including: Accrington, Blackburn, Burnley, Clitheroe, Darwen, Great Harwood, Haslingden, Padiham and Pendle.


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