Klober hits the perfect pitch with performance underlays

For roofs needing the highest standard of roof space ventilation, Klober’s Permo® air – classified as an air-open, low resistance underlay – offers an exceptional level of breathability.

In the past, variable performance of vapour permeable underlays led to the NHBC and BSI deciding that only air-open membranes could be used without supporting high level ventilation. Designed to meet this requirement and prevent condensation forming in the roofspace, Klober Permo® air has a water vapour resistance confirmed to be as low as 0.045 MNs/g.

BBA and IAB approved, Permo® air can be used for both cold and warm roof installations, and not only avoids the additional cost of supporting ventilation, but also interruptions in the roofline caused by traditional tile or slate vents. Being manufactured from polypropylene, it is also fully recyclable.

Unique to the roofing sector, Permo® extreme RS SK2 is an underlay that facilitates the laying of profiled and flat tiles to pitches as low as 12.5o – a problem with traditional underlays where existing windows, extensions or pipework may preclude a contractor achieving a sufficiently steep pitch needed for the preferred tile. This issue is particularly common with plain tiles which would typically require a pitch between 30-40⁰.

Enabling profiled tiles to be laid as low as 12.5° and flat tiles at 15°, Klober Permo® extreme RS SK2 offers high tear resistance, a shrink-resistant TPU coating and double self-adhesive edge strips which provide a permanent seal at laps and immediate weatherproofing. Its robust PES fleece also incorporates a capillary stop to control the formation of condensation.

Unlike traditional vapour permeable underlays which provide very limited weather protection if left unprotected, Permo® extreme has been designed to provide a temporary weatherproofing layer in its own right. Laid on 12mm ply board or OSB sarking board, it is simple to position prior to the edge tapes being peeled off for laps to be pressed into place.