What is a damp proof course (DPC)?

A damp proof course, or DPC, is a continuous moisture barrier built into a wall structure, usually positioned 150mm above ground level. It sits between the foundation and brickwork and acts as a physical block to capillary rise, stopping water that would otherwise travel upward through the masonry and into the interior of your home.

The barrier is typically made from slate, tile, bituminous material, or modern plastic membranes. Its position matters critically: it sits at the junction where the most water contact occurs, intercepting moisture before it can penetrate into the property.

When paving is laid around a building, the level of the finished surface becomes crucial to DPC performance. If new paving is raised above the DPC line, it can bridge the moisture barrier entirely. This bridging effect allows water to climb over the top of the DPC and into the wall, defeating its purpose and potentially causing damp problems inside. Professional paving contractors understand that the finished paving surface must always sit below the DPC level, typically at least 150mm below to maintain a safe gap. This is why surveying the existing DPC height before laying patios, drives, or pathways is part of proper site assessment.

For properties with existing damp issues or when undertaking major landscape work, identifying the DPC location and ensuring paving stays clear of it is a straightforward but essential step.