Platon membranes promise watertight basement

BBA approved Platon cavity drain membranes were specified as the structural waterproofing system for a new basement, part of major renovation works to a late Victorian property in Hammersmith.

BBA approved Platon cavity drain membranes were specified as the structural waterproofing system for a new 150m3 basement, constructed as part of major renovation works to a late Victorian property in Hammersmith.

Cavity drain membranes work on the principle of allowing water to penetrate the structure, but control it in the air gap and divert it to a suitable drainage point.

As part of the works, a concrete sump chamber was created in the new structural slab within the integral light well area to accommodate two submersible pumps.

This formed the drainage point for the waterproofing system.

Water from the pumps could then be discharged via pipes connected to external rainwater gullies.

Platon Multi membrane was fixed to the new basement walls using special Platon Brick Plugs, and fast track independent gypliner was then installed ready to receive insulated plasterboard.

In the new reinforced concrete floor, a chevron pattern of channels were cast in-situ with a slight gradient to enable ground water ingress to be directed to the sump chamber.

This method of transporting ground water to the sump chamber was adopted because the installation of preformed internal perimeter drainage channel, in this instance, would have undermined the structural integrity of the engineer's design at the wall/floor junction.

Another consideration was to construct the floor slab with a fall, but this would have compromised the required ceiling height.

Platon P20 cavity drain membrane, which has a 20mm deep stud was then loose laid to the floor slab and sealed to the wall using a proprietary wall/floor junction material.

Insulation was then laid on top of the P20 and overlaid with a 75mm reinforced sand and cement floor screed.

The Platon membrane system is supplied in the UK by Triton Chemicals and was specified and installed by North London based building contractors, Martinisation .

Unlike cementitious tanking systems, cavity drain membranes do not allow pressure to build up against the internal construction.

They are suitable for new build or renovation projects and minimal substrate preparation is required.

Depending upon the membrane selected, wall surfaces can be dry lined or plastered directly.

Timber floating floors or floor screeds can be installed over Platon floor membranes.

Back to top