Our high performance breather membranes, for use in construction and roofing, are fully certified and guaranteed to offer the best protection against condensation. Permavent breather membranes were fully certified for use in all roofing applications. Permavent breather membrane is good at controlling condensation that it is the only 3 layer roofing membrane to pass the air permeability test from the Building Research Establishment (BRE) and will offer the best option for use as a better alternative breather membrane to our rival brand leaders such a s Tyvek, Klober and Roofshield (when used as roofing felt).