Permo Air is the most breathable, air-open membrane on the market. It minimises the risk of condensation forming in the roof; particularly during the drying out period of a building.
Suitable for Cold and Warm Roofs.
Wind zones 1-3 with battened headlap.All wind zones with taped headlap.
Should be installed in line with the details set out in the BBA approved certificate and the terms laid down in BS5533
An unsupported underlay should provide a drape between rafters sufficient enough to ensure that water will run away from the batten fixing nail penetrations allowing draining from the eaves gutter
Contact between the membrane and the roof covering should be avoided during installation
Should be laid with a maximum drape of 15mm