At ADC Ltd, we provide cavity drain systems and cementitious tanking for basement waterproofing. For more information on basement waterproofing, please read on or feel free to call us today on 0117 952 0786 to arrange for one of our engineers to complete a site visit and survey.
Most cavity drain systems use a high density studded plastic waterproof membrane which acts as a dry lining to ceiling walls and floors. There is an air gap behind which allows water movement which is channelled into a drainage system which in turn drains to a gully where possible or a sump pump with non-return valves. It can then be drained away from the building.
The membrane is fixed using waterproofed plugs and all joints are sealed using a waterproofed tape. The internal finishes to the membrane can be rendered or dry lined. Alternatively, a water, sand and cement render can be applied, followed by a cementitious tanking system. This, in turn can be dry lined or a flush plaster can be applied.
Basement penetrating damp
Basement areas and retaining walls are particularly prone to penetrating damp due to increased water pressures at sub-ground levels. In most cases, below ground moisture will penetrate through up to ground level, therefore all plaster and backing coats will need to be removed up to the DPC (Damp Proof Course) level and possibly above.
Cementitious tanking systems
These involve applying two coats of waterproof sand mix with cement render onto prepared brickwork or block work. This is followed by the application of a cementitious waterproof tanking over the render followed with a further coat of waterproof render and forming a ranked wall / floor joint compound. When dry, the area can be finished with plaster, if necessary.
Cavity drain membranes
Provide an alternative to conventional cementitious tanking systems, which work by holding the water back. Cavity drain membranes work on the principle of allowing water to continue to penetrate the structure but control it in the air gap and divert it to a suitable drainage point. They do not allow pressure to build up against the internal construction and the air gap behind the membrane allows the structure to breathe and to some extent, to dry out.
The membranes are loosely laid on floors and fixed to walls using special plugs and sealing materials, with little or no preparation required to the substrate. Once the membrane has been fitted, wall surfaces can be dry-lined or plastered directly and floors can be screeded or a floating dry board system installed.