How Damp Proof Course (DPC) is supplied What is it? A damp proof course (DPC) is a barrier, typically made of materials like bitumen, plastic, or slate, that is installed in the walls of buildings to prevent moisture from rising through the structure. Specifically, it protects against: Uses: 1. Rising Damp: This occurs when groundwater moves upward through the porous materials of the building, such as brick or mortar. The DPC prevents this moisture from penetrating the walls above the course. 2.