Permavent Black 1m x 50m - Breathable Roofing Felt - Breather Membrane - 120gsm
BS 5534: 2014 Code of practice for slating and tiling. Elongation at max. tensile force (MD), % 100. tensile force (CD), % 100. Maximum tensile force (MD), N/50mm 240. Water vapour transmission (sd),m 0.02.