Basement Waterproofing - The Problem

Many buildings contain an uninhabitable, mouldy and dank basement with no waterproofing protection. Cellar walls, which typically form the foundation of the building, are generally sited below outside ground level and below the buildings damp proof course. Accordingly walls are constantly subject to conditions favourable to penetrating damp and water ingress via capillarity and/or hydrostatic pressure.

In order to convert below-ground structures into habitable and functional basement accomodation it is necessary to provide a fully sealed basement waterproofing system to ensure the moisture in the walls and floors is not permitted to migrate to the internal surfaces of the renovated living accomodation.

Cellar Waterproofing Solutions

The two most common tanking methods for waterproofing walls are:

Structural Waterproofing: This is multi-coat, pore-blocking slurry that is sandwiched between two coats of dense cement render. The tanking slurry contains polymers designed to enhance adhesion and increase tensile strength. Once applied the tanking is able to withstand external water pressure and maintain a dry environment by creating a physical barrier to water entering the basement area.

Cavity Drain Tanking Membrane: This is a robust dimpled waterproof membrane that can be applied to almost all below ground building structures that are affected by dampness or water ingress. The impervious studded membrane creates continuous air cavities to permit ample water drainage and air circulation, allowing underlying substrate to both drain and breath. The fully sealed basement membrane arrangement can be enhanced by the provision of sump and pump drainage systems to ensure water ingress behind the membrane is channelled, drained and discharged from the building.

Both tanking methods ensure that the damp and dank walls remain isolated outside a dry cosy interior living area.

Tanking Products

Tanking slurries:
Tanking slurries are typically available as cement/quartz/acrylic polymer blends supplied in powder form. The formula mixes with water to make a cementitious slurry compound that sets to make a completely waterproof barrier over a masonry surface.

Mesh Faced Membrane:
High density polyethylene basement tanking membranes are fixed to walls and floors and are available in a variety of forms, each incorporating an air gap for the movement of water vapour. The most commonly used are a plain studded membrane, a foil faced insulating membrane and a DIY mesh faced membrane, the latter giving prospect for the direct application of plastered finishes. A range of diy tanking accessories, including masonry fixing plugs and butyl bonding products are also available to ensure fixings and joints remain impermeable.