Product Description:

Our DPC Polythene is a flexible damp proof course supplied in a 450mm x 30m roll, the widest in our range. It is used where a barrier needs to cover the full depth of a cavity wall in a single sheet, for stepped DPCs and cavity trays across wider cavities, beneath sills, thresholds, and door openings, under timber sole plates and sleeper walls, and for general moisture separation work where narrower rolls would need joining.

The extra width is what makes this roll so adaptable. Modern cavity walls, with a full or partial fill of insulation, are often considerably deeper than older construction, and a stepped DPC or cavity tray has to span from the outer leaf, rise across the cavity, and finish on the inner leaf in one continuous piece. At 450mm, there is enough material to do that on deep cavities without joins, which are the weakest point of any damp barrier. It is equally useful for separating timber from masonry, laid beneath sole plates, wall plates, and sleeper walls to keep ground moisture out of the timber above.

Polythene DPC is lightweight, easy to cut with a knife, and can be cut down lengthwise to produce narrower strips, making a single roll a practical stock item for jobs needing several widths. Lay on a fresh mortar bed, lap joints and corners by at least 100mm, and link the DPC with the floor damp proof membrane so protection is continuous. Keep it clear of render, pointing, and raised external ground levels, which would allow moisture to bridge around it.