Permo Extreme is a tear-resistant membrane designed for use on low roof pitches and complex roofs. Whilst it includes two fitted self-adhesive strips, which provide a permanent seal of overlaps and immediate weatherproofing protection against wind, rain and snow.
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
The underlay should be laid on a 12mm ply/OSB and then counter battened. Butylon tape should be laid underneath where the counter battens are going to be fixed in order to seal around any nail penetrations.
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 and after installation.
Permo Extreme RS SK 2 should be laid minimum 10mm, maximum 15mm drape.