Permo Extreme is a tear-resistant roof underlay designed for use on low pitched roofs and complex roofs, down to a minimum roof pitch of 12.5° for profile tiles, 15° for slates and 22.5° for plain tiles. This makes Permo Extreme roof membrane the perfect solution for extensions and lean-tos, particularly as the roll is available in a half-size for smaller projects. The membrane is fleece lined to control condensation, whilst it's fitted with self-adhesive tape, which provides a permanent seal of overlaps and immediate weatherproofing protection against wind, rain and snow. Permo Extreme is also highly temperature resistant from -40°C to +100°C and can be deemed as a primary barrier when installed with Klober accessories and covered by a UV protected layer.
High resistance membrane so requires ventilation.
Minimum roof pitch of 12.5° for interlocking tiles, 15° for slates and 22.5° for plain tiles.
Wind zones 1 - 5
Butylon tape should be laid on top of the membrane and underneath where the battens are due to be fixed - it is essential that the batten nail passes through the tape.
An unsupported underlay should provide a drape between the rafters sufficient to ensure that any water will run away from the batten nail penetrations, allowing drainage into the eaves gutter.
Contact between the membrane and the roof covering should be avoided during and after installation.
Permo Extrreme RS SK2 should be laid with a maximum drape of 15mm.