Klober has launched an air-open underlay for ventilation performance.

For new builds, particularly with complex roof designs, underlay performance is put under greatest strain during the critical drying out period. This variable performance of vapour permeable underlays has led to the decision by the NHBC and the BSI that only air-open membranes can be used without supporting high level ventilation. Klober Permo air prevents condensation forming in the roofspace by offering an exceptional level of breathability. Its water vapour transmission sd-Value is 2736 g/m²/day and its water vapour resistance (which has been tested by the BBA) confirmed to be as low as 0.03 MNs/g. As a result, it has also been specified for roofing upgrades of many high profile and historic buildings.

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