For roofs needing the highest standard of roof space ventilation, Klober 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 transmission sd-Value of 0.009m and its water vapour resistance confirmed to be as low as 0.045 MNs/g. As a result, it has been specified for roofing upgrades of many high profile and historic buildings.
For new builds, particularly those with complex roof designs, underlay performance is put under greatest strain during the critical drying out period. Permo® air’s use on both cold and warm roof installations avoids the additional cost of supporting ventilation and offers the additional benefit of having been tested for wind uplift resistance by the BRE. It found the membrane to be suitable for use up to Zone 5 on the BS 5534 wind speed map (with laps taped or battened in zones 4 and 5).
BBA and IAB approved, Permo® air 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.
More generally, Klober is one of Europe’s leading manufacturers of pitched roofing products. It has one of the most extensive ranges available today including air-open and vapour permeable underlays, tile and slate vents, lead-free flashings, air barriers, dry fixing, solar installation accessories, floor and wall vents and roof safety products, having done so since 1960. Beyond the best performing products and customer service in the sector, Klober also offers unrivalled training and technical support to its customers.