No, a DPC (Damp Proof Course) should generally not be below floor level.
The purpose of a DPC is to prevent rising damp from the ground penetrating the walls of a building. The reference text states a DPC should be positioned a minimum of 150mm above the external finished ground or paving level.
Having it below floor level would effectively negate its effectiveness as moisture could bypass the DPC and rise into the wall above the floor.
Why DPCs Need to be Above Ground Level:
- Preventing Rising Damp: DPCs act as a horizontal barrier to stop moisture from being drawn up through the wall via capillary action.
- Building Regulations: Most building codes specify minimum heights for DPCs above the external ground level.
- Maintaining a Dry Interior: A properly installed DPC contributes significantly to a dry and healthy indoor environment.
Potential Issues with a DPC Below Floor Level:
- Damp Penetration: Water can bypass the DPC, leading to damp walls.
- Structural Damage: Prolonged dampness can weaken the structure of the building.
- Health Risks: Damp conditions can promote mold growth, which can lead to respiratory problems.
Therefore, a DPC's effectiveness is reliant on its placement above the external ground level and certainly not below the floor level.
