External walls that are plastered and then painted with a good quality paint usually resist water penetration for many years, especially where paint is renewed as necessary.
Surface cracks may appear in the plaster but these can easily be repaired using a latex-modified plaster or even a coating of Acryl Fibre. Penetrating Damp is most often associated with face brick buildings where either the bricks are more porous due to ineffective manufacture or where the mortar between the bricks has deteriorated. This may be the result of an initial weak mortar mixture or deterioration due to either frost, or in some cases, acid rain.
Penetrating Damp has historically been prevented by sealing the exterior walls with paint, brick sealants, varnish and even epoxies. Whilst they effectively stop water penetration, the down-side is that they stop the building from “breathing” which can cause further problems on the inner surface of the walls. A better method is to treat the exterior with a water repellant which still allows the substrate to “breathe”. Such products contain silanes and siloxanes in solution in either white spirit or, from a more eco-friendly standpoint, water. Raincheck (solvent-based) and Raindance (water-based) are 2 such products. These products penetrate the exterior surface to a depth of 2-3mm and have to be renewed every 2-3 years due to the adverse effects of Ultra Violet rays. However, Safeguard Europe, the leaders in dampproofing innovation, introduced in 2012 a product called Storm Dry which is cream-based, like its dampproofing cousin Dryzone Cream. This cream, containing the same silanes and siloxanes, penetrates the substrate to a depth of 2-3cm and as such is totally unaffected by UV, allowing us to confidently give a guarantee of 20 years against further water penetration.
For more information please contact us on 011 708 3603 or 021 982 5131.