A DPC layer is usually laid below all masonry walls, regardless if the wall is a load bearing wall or a partition wall. A damp-proof membrane (DPM) is a membrane material applied to prevent moisture transmission.

Where does the DPM go?

DPM membranes are laid either under a new concrete slab or on top of it to prevent moisture transmission. Ordinarily you will have a bed of hardcore on the ground then either a blinded surface and a DPM before a layer of concrete, or you place the DPM on top of the concrete slab before the final flooring.

Where should DPC be installed?

Lay the DPC on a full even bed of fresh mortar in one continuous length, for the full width of the leaf. Provide at least a 100mm overlap at any joint or corners. The DPC must not obstruct the cavity. Ensure the external edge of the DPC is visible and not bridged by mortar when completing pointing of the mortar joint.