VapourTech® Brane® VHP is classified as a Water Barrier and Class 4 Vapour Permeable membrane. Very high levels of water vapour are allowed to absorb and diffuse through the core non-woven structure, ensuring that condensation risk is controlled, while outside liquid water cannot penetrate inwards. VapourTech® Brane® VHP is chemically non-reactive in conjunction with treated timber and salt conditions close to coastlines.