BU653 Damp-proof membranes to concrete slabs

Damp-proof membranes (DPMs) or concrete underlays are necessary under on-ground concrete floor slabs to prevent moisture from the ground passing through the slab and damaging the interior finishes, fittings and contents.

The use of a DPM is mandatory under slabs on ground for all habitable spaces and under slabs for garages or ancillary buildings that may be used as habitable spaces in the future.

This bulletin outlines the selection, design and installation requirements for DPMs. It updates and replaces Bulletin 469 of the same name.