Technical Booklet C Site Preparation and Resistance to Contaminants and Moisture·Page 26·5.17
Damp-proof membrane material specifications
The DPM must be formed from polyethylene sheet at least 300 μm thick (1200 gauge) or three coats of cold applied bitumen solution or similar moisture and water vapour resisting material.
The DPM could be formed with a sheet of polyethylene, which should be at least 300 μm thick (1200 gauge) or three coats of cold applied bitumen solution or similar moisture and water vapour resisting material.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/Technical Booklet C - Site Preparation and Resistance to Contaminants and Moisture.pdf