28/09/2026
🧱 Brickwork to DPC (Damp Proof Course) Level
Damp in a new extension is very hard to put right once the walls are built and plastered, and it usually comes back to what happens at the DPC, or damp proof course, in the first few courses of brickwork. That's why this stage of the build gets checked so carefully before anything else goes up.
The DPC is a waterproof layer built into the walls, sitting at least 150mm above the ground outside, which stops moisture from the ground travelling up through the brick and blockwork. It also has to link up properly with the damp proof membrane under the floor, so the whole building has one unbroken barrier.
The problems that show up later are usually simple ones. A patio or path gets laid too high and covers the DPC, or mortar drops into the cavity and builds up where it shouldn't. Both let moisture bridge across, and both are much easier to prevent at this stage than to fix afterwards.
Building control inspect at DPC stage, so nothing gets built above it until it's been checked and signed off. Getting it right here is what keeps the walls above dry.
If you're planning an extension and want to know what happens at each stage of the build, get in touch and we'll talk you through it.
Build with confidence. Build with compliance. Build with MJG!