NHBC and BSI have made the decision that only air-open membranes could be used without supporting high level ventilation due to the widely varying performance of vapour permeable underlays.
Klober Permo air offers an exceptional level of breathability, with a water vapour transmission sd-value of 2736 g/m2/day and a water vapour resistance which has been independently confirmed to be as low as 0.03 Mns/g. Klober Permo air is therefore ideal for roofs needing the highest ventilation performance.
Countless historic buildings have used it to upgrade and during the critical drying out period on new builds it is used to provide unparalleled performance.
