Product Description:

Our DPC Polythene is a flexible damp proof course supplied in a 150mm x 30m roll, laid within masonry walls to stop moisture rising from the ground into the brickwork and blockwork above. The 150mm width is sized for thicker walls, including 140mm blockwork used for party walls, separating walls, and load-bearing construction, and it is used on extensions, garages, outbuildings, and new build work where a standard narrow DPC would not cover the full width of the leaf.

A damp proof course only works if it runs across the entire width of the wall. Brick, block, and mortar draw moisture upwards by capillary action, and any section left uncovered at the edge of a wider block gives that moisture a path around the barrier and into the wall above, leading to rising damp, damaged plaster, and decayed timber. The 150mm width gives full coverage to 140mm blocks with a small margin, so the DPC can be set flush with the face of the wall on both sides without leaving a gap.

Polythene DPC is lightweight, easy to cut with a knife, and quick to lay, unrolling straight onto a fresh mortar bed at least 150mm above external ground level with the next course laid directly on top. Joints and corners should be lapped by at least 100mm, and the DPC must link with the damp proof membrane in the floor so the protection is continuous where wall meets slab. Keep it clear of render, pointing, and raised external ground levels, which would allow moisture to bridge around it.