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

It has a water vapour transmission 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.

With BBA and IAB approval and an increasing network of merchant stockists, it has been used to upgrade countless historic buildings and provides an unparalleled means of preventing condensation on new builds during the critical drying out period.