Liquid Damp Proof Membrane [DPM]

[see also the Vapour Barrier section of this glossary]

A liquid DPM is, as the name suggests, a liquid chemical that is applied to a clean, sound and flat concrete sub floor to prepare it to take a either a fully glued down floor installation or a floated floor. It is normally applied in two separate coats with a roller brush. The second coat should be applied in a direction at 90 degrees to the first to ensure that the screed is fully covered and that there are no bare patches or tiny holes remaining. Where a glue down installation happens, a liquid DPM doubles as a primer for the flooring adhesive. In such cases it is important to use compatible adhesive and liquid damp proof membrane products. A high performance liquid DPM will drastically slow down the evaporation of moisture from a solid floor screed.

The manufacturers detailed instructions and advice should be followed precisely and it is important that the sub-floor is not walked over between coats of DPM and adhesive. Technical data from the screed manufacturer should also be consulted.

Expert advice should be sought with regard to appropriate solutions to damp screed conditions prior t0 floor covering being considered.