Powerlon VCL 170 has been manufactured from reinforced polyethylene with a high tensile scrim reinforcement to act as a barrier to block interstitial condensation, caused by warm air and moisture reaching insulation. Powerlon VCL 170 will increase a buildings airtightness as its impermeable. This means it contributes to BS 9250 for airtightness and BS 5250 for control of condensation. This Powerlon VCL 170 is air and vapour control layer that is applicable to roofs, walls and floors. Powerlon VCL 170 Specifications Length: 50m Width: 2m Weight: 210gsm Vapour Resistance: 336MNs/g Colour: Clear