Protection from adverse weather is of paramount consideration for any housing or commercial building. To this end material ideally suitable in combating the harshest climatic conditions must be especially included in the structure’s composition. This makes it vital to choose the right protective materials during construction. Buildworld stocks multiple ranges of products designed and manufactured by top brands meeting the requirement of British Standard (BS) compliances. The threat of water seepage can be countered through Damp-Proof Course (DPC) or Damp-Proof Membranes (DPC) or at times, even a combination of the two.
DPC and DPM are well known to ward off moisture but differ in how and where they are applied. When there is a chance of water seepage through capillary action, DPCs are used vertically at ground construction or horizontally at the base wall to stop the damp from penetrating further. DPCs may comprise of metal, plastic, felt paper, slate and are now also made with modern technology in the form of bricks. A mason typically rolls out a layer of DPC over a bed of cement, cutting it as per the required size and adds another layer on top. This DPC is applied to a height of 150mm above the ground level. This way, if it rains the wall will not soak moisture and will remain insulated from damp ingress. A DPC may also be installed flat all along under the inner skin of a wall or floor, so as to combine it with a DPM.
DPMs usually are thick plastic or polythene or polypropylene sheets made in different grammages and are quite bulky. These are generally spread out in a single sheet along the concrete slab to stop groundwater seepage into the floor above. DPMs have to be carefully extended at joints to reach the DPC applied at walls.
The basic difference between DPC and DPM is that the former is used in the walls and the latter is incorporated into the flooring. An “Oversite” is when the mason first installs a hard layer, then a soft layer of sand, with a layer of DPM and concrete on top.
Sometimes old houses may not have any damp proofing and therefore require a “Retro” DPC fitting, which although tedious go a long way in keeping damp away while retaining vintage architecture. The fitting requires the wall to be cut into 1-metre sections with a heavy chainsaw followed by the DPC insertion into the gap, with slate used to fill the remaining gap. The entire house has to be covered section-wise, in order to ensure that each DPC overlaps the next one.