Damp proofing in construction is a type of moisture control applied to building walls and floors to prevent moisture from passing into the interior spaces. Damp problems are one of the most frequent problems encountered in homes. Rising damp is the effect of water rising from the ground into your property. 2  The damp proof course may be horizontal or vertical. 3  A DPC layer is usually laid below all masonry walls, regardless if the wall is a load bearing wall or a partition wall.