Where should chemical damp proofing be installed ?
You should choose a chemical DPC system that is specifically designed to be introduced into the mortar joints. The mortar presents the only continuous passage ascending up a wall through which water is able to rise. Therefore a mortar bed joint is the only layer that can function as a damp proofing layer. Introducing a DPC into just each brick or block unit along a stretch of wall will not stop the water rising through the joints between. In accordance with BS6576:2005 a DPC should be sited at least 150mm above external ground level and internally beneath ground floor joists, or close to the floor if solid. If the two are incompatible please phone our help line for DIY or trade advice.
