Permavent APEX is a 3 layer breather membrane for use as a pitched roof underlay. Permanent APEX is both vapour and air permeable providing unique condensation control which eliminates the need for low or high level ventilation. Permavent APEX also provides a secondary barrier to water ingress.
APEX has been endorsed by NHBC for use as an unsupported roof underlay in cold pitched roofs without the need to provide any ventilation at either high or low level. Permavent APEX is fully compliant with BS5534 and the integrated tape allows APEX to be installed in all UK wind zones, as well as giving added watertightness on low pitch roofs.