5.1.19 Damp proof course
Damp proof courses shall adequately resist moisture from reaching the inside of the building. Issues to be taken into account include:
- positioning of DPCs
- DPC materials.
5.1.19.1 Positioning of DPCs
DPCs should be:
- positioned a minimum of 150mm above external finished ground or paving level
- linked with any DPM
- of the correct width and fully bedded
- either welded or lapped by 100mm minimum
- impermeable.
Figure 9: DPC at least 150mm above finished ground level
Figure 10: Stepped DPC levels on sloping sites
Where homes are ‘stepped’ on a sloping site, care should be taken to link DPCs and DPMs so that all parts of each home are protected.
5.1.19.2 DPC materials
Acceptable materials for DPCs include:
| Bitumen based materials | BS 6398, BS EN 14967 |
| Polyethylene (except as cavity trays in walls, below copings and in parapets) | BS 6515, BS EN 14909 |
| Thermoplastics and elastomers | BS EN 14909 |
| Proprietary materials | Proprietary materials Technical Requirement R3 |
DPCs and flexible cavity trays should be of the correct dimensions. At complicated junctions, preformed cavity trays of the correct type and shape should be used.
Brick DPCs are only suitable to resist the upward movement of moisture and should:
- consist of two courses of engineering bricks, laid broken bond
- be bedded and jointed in a 1:¼:3, cement:lime:sand, or equivalent, mortar.
Last updated: 2nd January 2025