Plastic Moisture Barrier

Overview

Builders plastic (200µm polyethylene membrane) is widely used in the building industry as a moisture barrier.
For solid timber floors install the plastic membrane on top of the concrete slab and then install battens / plywood over the plastic. If you are gluing the flooring direct to the slab, you will probably need to use an epoxy moisture vapor barrier instead (see our glue & seals section).
Floating floor underlays often already have a plastic backing moisture barrier built in. Otherwise, install the plastic membrane over the flat subfloor then install the underlay (eg Regupol), finally install the floorboards
Where two plastic sheets meet, overlap the edges by 200mm and tape the joints. Best practice is to bring the plastic up the walls and then cover them with the skirting