Damp proofing above ground.
Preventing Rising Damp:
To prevent rising damp from affecting walls, houses have been built with physical DPCs for many years. However, these physical barriers do not always prevent rising damp from occurring. Especially in older houses, physical DPCs can become damaged over time or, in some cases, were installed improperly. In old properties Slate was used to prevent rising damp but over the years the ground & property move which breaks down the solid slate DPC allowing moisture to breach & be forced up into the internal substrate. Some older property simply never had a damp proof course!
Additionally, when houses are being modernised or extended, building works can affect built-in physical DPCs. With a change of the ground level, for example, the physical DPC layer can be bridged, and rising damp can appear where there had been no problem before. In such cases, a remedial DPC needs to be installed to prevent rising damp from recurring. Also lowering the ground levels or creating a drainage system to guide the ground moisture / rain fall away from the property footing.
Rising damp often has negative effects on the internal plaster, wallpaper, paints, and skirting boards. To repair the effects of rising damp the source of the problem itself must be treated and the decor on internal walls must then be repaired ready for new decoration.
Treating rising damp on Internal walls:
Before a treatment to stop rising damp on internal walls can begin, all skirting boards around the affected area need to be removed. Additionally, all salt-contaminated plaster needs to be hacked-off to a minimum of 300 mm above the last detectable signs of dampness or salt contamination. We would generally go to a hight of around 1400mm, depending on the situation / survey report. Once the brickwork has been exposed, the treatment of rising damp can begin. By using DryZone damp proofing cream or DryRod damp proofing Rods a remedial DPC can be injected directly into the masonry, ensuring a targeted treatment of the problem. Regardless of whether Dyzone or Dryrods are used, holes must be drilled into the lowest accessible mortar course that is still at least 150 mm above the exterior ground level. These are typically drilled at a regular interval of 100 – 120mm, with a diameter of 12 mm. When the holes have been prepared, the rising damp treatment can be injected. Injecting a damp-proof cream or inserting damp-proofing rods ensures a targeted, highly effective treatment of rising damp.
Following the DPC Injection we would either use a Cementitious render system Including a specialist Tanking slurry, finishing with a skim coat ready for decoration. Or a waterproof slim-line membrane system followed by drylining the walls & skim coat ready for decoration. New skirting boards will be installed in most cases