Do I still require a vapour barrier with NUDURA?
According the standard ASTM E 96, to qualify as a vapour barrier, a material must not exceed 45 ng/Paּsּm².This unit denotes the ‘permeance’ of the material, meaning how much moisture per force applied (air pressure), in a second over a square area. Our EPS foam has a permeance value of 36 ng/Paּsּm²,therefore the NUDURA Type II EPS qualifies as a vapour barrier. Better recognize.