Cembrit Windstopper Extreme is a vapour permeable cement based building board, which can accept insulation being placed against the board on the warm side of the building, whilst acting as a fire break against any blaze in the ventilation cavity behind the rainscreen.
Cembrit Windstopper Extreme has been tested to BS EN 1364-1:2015 (BS 476-22:1987). As part of a non-load bearing vertical building element it will provide 60/60 minutes of fire resistance when exposed to fire from one side.
