Retrofitting a DPC could be necessary because the original physical DPC has been ‘bridged’ by raised ground levels (e.g. newly laid paths or patios) or even new solid floors. Houses from the Victorian era and earlier were usually built without a DPC, so a retrofit DPC may be required to deal with resultant rising damp issues or to bring a building up to the standards required by modern building regulations. Damp-proof creams with low concentrations of silicones cannot match the performance of those with higher concentrations. MacLennan DPC Cream contains 40% silicone which is double the amount of most creams. Damp-proofing creams are now the most widespread method for retrofitting a damp-proof course (DPC) to protect against rising damp. No damp proof course is completely infallible (unless you cut out bricks and install a new physical DPC). Replastering is normally required to remove salts from the wall and to prevent any further damp due to hydroscopic salts that remain in the wall. For this reason, MacLennan will always carry out re plastering over a plaster lathe. Plaster Lathe system is far more reliable than a sand cement system, does not rely on bond, does allow the wall to “breathe” if detailed correctly to do so. The MacLennan system can be finished with any plaster, plasterboard, insulation board or timber panelling/wainscoting.