Glidevale Protect's VP400 vapour permeable roofing underlay with excellent nail-tear and tensile strength while remaining lightweight and easy to cut. Used as an underlay for warm or cold roof construction, it helps to avoid the risk of roof-space condensation. Easily marked with a chalk line. 100% waterproof with unrestricted use in windy areas. Providing a secondary line of defence against wind-driven rain and snow after the roofcovering is installed, VP400 offers unrestricted use for wind uplift across the UK and Ireland using 345mm batten gauge. UV and heat-resistant. Weight: 180g/m² Vapour Permeability / Resistance 0.11MNs/g High Performance & Watertight Use in Warm or Cold Pitched Roof Constructions on Any Roof Shape or Building Type Weight: 180g/m² Vapour Permeability / Resistance 0.11MNs/g High Performance & Watertight Use in Warm or Cold Pitched Roof Constructions on Any Roof Shape or Building Type