07/08/2026
There's a very important reason why we sell only 9inch and above DPC in our showrooms. A 6inch DPC or narrower has no any business to do in wall construction in Ghana. A damp-proof course (DPC) is technically deliberately made a little wider than the wall thickness for a few practical reasons:
1. To protect any rendering or plaster on both faces
Walls are often finished with plaster or render on one or both sides after construction. If the DPC were cut exactly to the wall's structural width, the plaster/render layer applied afterward would sit outside the edge of the DPC and would have no damp protection — moisture could rise through the render even though the main wall is protected. Extending the DPC slightly beyond the wall face ensures the finish coats are also covered.
2. To prevent moisture bridging at the edges
If the DPC stops flush with or short of the wall face, capillary moisture can creep around the exposed edge of the DPC (through mortar squeezed out during laying, for instance) and bypass it entirely. A wider DPC leaves no exposed masonry/mortar path at the edges for water to sneak past.
3. To form a slight drip/overhang
Where the DPC projects a little beyond the wall face, it can act like a small drip edge, encouraging water to fall away from the wall face rather than track back in against it — similar to how a drip groove works under a sill or coping.
4. To allow for site tolerances
Bricklaying and masonry work are never perfectly precise. A slightly wider DPC gives tolerance for minor misalignment during laying, ensures full coverage even if the wall isn't perfectly straight, and allows for proper lapping at joints and corners without any gaps in coverage.
In short: if the DPC were exactly the same width as the wall (or narrower), any finish layer, mortar squeeze-out, or minor construction inaccuracy could create a path for rising damp to bypass the barrier. Making it wider ensures a continuous, full break in capillary movement across the entire wall cross-section, including finishes.
