Damp Proof Course (DPC) Explained

By Vystra · 1 October 2026

Ever seen a wall with peeling paint and damp patches near the floor? That's usually rising moisture — and a damp proof course is what prevents it.

What a DPC is

A damp proof course (DPC) is a waterproof layer built into the wall to stop ground moisture rising upward through the masonry by capillary action.

Why it's essential

Without a DPC:

• Walls stay permanently damp near the base.
• Plaster and paint peel and blister.
• Efflorescence (white salt patches) appears.
• Over time, the structure weakens.

Fixing damp after construction is difficult and expensive — a DPC prevents the problem from the start.

Where it goes

The main DPC is provided at plinth level — between the foundation and the walls above — forming a continuous barrier around the building. Additional damp proofing is used around bathrooms, kitchens and terraces.

Common DPC materials

• Cement mortar with a waterproofing compound.
• Bituminous layers.
• Waterproof membranes.

The key rule

A DPC only works if it's continuous and unbroken. Any gap lets moisture bypass it. This is why it must be laid carefully, not rushed.

The takeaway

A damp proof course is a small, inexpensive layer that prevents years of damp problems. Skipping it to save a little now leads to costly repairs later. With BuildVystra you can include DPC and waterproofing as tracked line items in your estimate — so nothing essential gets forgotten.

Frequently asked questions

What is a damp proof course used for?

A damp proof course (DPC) is a waterproof barrier that stops ground moisture rising up through walls by capillary action. Without it, walls stay damp, plaster and paint peel, and the structure can deteriorate over time.

Where is DPC provided in a building?

DPC is typically provided at plinth level, between the foundation and the superstructure walls, so moisture from the ground cannot travel up into the walls. It may also be used around bathrooms and other wet areas.