Cavity Drain Membrane

For our basement conversions, we use the cavity drainage membrane method which is used as a below ground water proofing material.

The cavity drain membrane works on the principle of allowing water to continue to penetrate the structure of the building, but control it in the air gaps between the cavities of the membrane and divert it to a suitable drainage point.

Pressure can not build up against the internal construction and the air gap behind the membrane allows the structure to breathe and to some extent dry out, i.e. it keeps the dampness as moisture rather than a liquid.

This method of cavity wall drain membrane installation is a great solution for older homes, or listed buildings.

cavity drain membranes

The Membrane

The main component of the system is an H.D.P.E (High Density Polyethylene Extrusion) membrane with a thickness of 0.6mm and a stud formation with a height of 9mm.

The studs serve to hold the drain membrane away from the areas that are being treated, allowing an air gap of 5.5 litres per m². Water vapour can move unhindered in all directions and damp pressure equalisation is achieved.

cavity drain membranes

The Ideal Internal Wall for Basement Conversions

The cavity membrane allows for better air flow, so no condensation can occur. The surface of the wall can be decorated immediately, and electric cables, plumbing pipes, etc. can be concealed within the wall. The cavity membrane is resistant to cracks, vibration and building movement, and is carries a 20-year guarantee.

The Cavity Drainage Membrane can be installed on walls, ceilings and floors using waterproof sealing plugs, battens and plasterboard and then skimmed with finish plaster allowing you to decorate your basement conversion to suit your intended use.

Floor areas are finished with tongue and groove pre-treated boards or stone slab, raised between approximately 30mm-60mm depending on the type of flooring specified by the surveyor. This is essential to allow constant moisture to evaporate behind the H.D.P.E membrane.

Basement Conversion Water Management

Where water ingress is noted, we always recommend that a sump with an automatic pump be incorporated into our basement conversions.

Water entering the building through the walls is controlled behind the Membrane and diverted to the Aqua Channel at the base of the wall. The water enters the Aqua Channel through pre-drilled 19mm drainage holes set 70mm apart along its length and is then diverted to a suitable drainage point, either natural or a sump and mechanical pump. Jetting eyes (cleaning ports) can also be incorporated into the aqua channel.

Once the water pushes the flotation device to a certain level the pump will automatically switch itself on and pump the water to a nearby drain. Once the floatation device returns to its original level the pump will then switch itself off. Insulation is fixed to the lid to prevent noise vibration.

cavity drain membrane pump

Get in touch to discuss how our team of experts can complete your basement conversion on time and within your budget. Our sales team are helpful, knowledgeable and never pushy.

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