House and Leisure posed the question to Sonia Nogueira, Operations Manager at Coprox – a South African leader in waterproofing products for masonry structures. She had the following to say: The complexities of waterproofing are vast. Therefore, not unlike a medical practitioner, a quick and simple cure to your problem can’t be recommended without a proper diagnosis. The following guidelines are for the waterproofing of a porous or dense masonry (cement) substrate. Porous masonry substrate A porous masonry substrate is a masonry surface (plaster, screed, mortar or brickwork) that can still absorb an appreciable amount of water. For example, a wood floated floor screed. To see if the surface is porous enough, throw a full glass of water onto it. If an appreciable amount of it is absorbed into the surface, it is porous. If the water runs like that off a duck’s back or only a small amount is absorbed, the surface is dense.
- Remove any efflorescence while dry, using a stiff bristle scrubbing brush. (Efflorescence is a white fluffy deposit on a masonry surface, caused when soluble salts present in masonry are carried with moisture to the surface. This deposit can normally be brushed off when dry, but usually disappears with time after rains or washing with water.)
- Clean the surface – remove dust, dirt and all other foreign matter.
- Apply two coats of Coprox Masonry Waterproofing. The crystalline properties of Coprox Masonry Waterproofing migrate into the capillaries and shrinkage cracks of a porous masonry surface, impeding the progress of moisture in and out of the protected surface.
Dense masonry substrate A dense masonry substrate is a smooth floated masonry surface, whereby the screed or plaster has been floated using a steel or rubber float, thus not allowing water to be absorbed into the surface.
- Remove any efflorescence while dry, using a still bristle scrubbing brush.
- Remove dust, dirt and all other foreign matter.
- Surfaces must be completely dry and free of any moisture before application commences.
- Apply two coats of Coprox Cobond mixed with Coprox Masonry Waterproofing according to instructions.
Visit their website or call them on 011-579-4300 for more information or technical advice.