Ruukki diffusion membrane effectively prevents condensation from forming under the roof covering and prevents it from entering the roof structures and insulation. Proper ventilation quickly dries the diffusion membrane. The designer's task is to provide the correct roof ventilation solutions, taking into account the specific construction. To ensure air circulation between the roof covering and the diffusion membrane, air inlet and outlet must be provided. 2 integrated adhesive tapes 3 functional layers Weight: 145 g/m2 Sd = 0.030 m Sold in rolls of 75 m2 and 30 m2.