8 handy hints for installing horizontal damp proof course (2024)

1. The inner leaf damp proof course must link with the upstand to the damp proof membrane, by a minimum of 50mm and be sealed to it. This is to ensure a continuous barrier against damp, this includes where low level cills are present ie doorways.
2. Lay the DPC on a full even bed of fresh mortar in one continuous length, for the full width of the leaf.
3. Provide at least a 100mm overlap at any joint or corners.
4. The DPC must not obstruct the cavity.
5. Ensure the external edge of the DPC is visible and not bridged by mortar when completing pointing of the mortar joint.
6. External render must not bridge the DPC.
7. Ensure the lean mix cavity fill material is at least 225mm below the lowest DPC .
8. Ensure the dpc is a minimum 150mm above external ground level.

When do you need to use a stepped DPC?

If you are building on a sloping site you may need to install a stepped DPC. The DPC must be stepped in the masonry coursing so that it is never less than 150mm above the finished ground level as shown in the diagram below: