Permo sec metal is a vapour permeable waterproofing barrier that is installed as a separating layer between copper, zinc, aluminium and stainless steel standing seam roof finishes and the supporting deck. Properties Length: 25m. Width: 1.5m. Roll size: 37.5m2. Roll weight : 14.5kg. Weight: 390 gsm. Thickness: 8.5mm. Reaction to fire: Class E. Resistance to fire: -30C to 80C. UV exposure: 4 months. Application Can be laid over rigid insulation or timber boarding. Suitable for roof pitches over 3. Material Outer layer of polypropylene mesh bonded to a vapour permeable membrane. 4 layer fleece foil combination of polyolefin, hydrophobic treatment and PP monofilament mesh.