Vapour Diffusion

Binder cross laminated timber BBS are diffusion open and therefore allow the proper motion of the vapour through the outside components.

This positive building physical characteristic of BBS and its characteristic to absorb room moisture without damage, [absorption characteristic], decisively adds to a comfortable and balanced room air condition.

The all-over glue grooves of BBS are diffusion open. Tests by the glue manufacturer prove that the usual glue grooves show the same diffusion resistance as a 35 mm thick spruce board. According to this BBS is diffusion open, but has a vapour inhibiting effect. These two positive qualities are important criteria for comfortable room air conditions. The glued one-layer boards of BBS do not have any effect on the diffusion behaviour of the element. BBS constructions are basically processed without vapour barriers and wind brakes.

BBS reacts to changing circumstances in the room air conditions, adapts well to them, and contributes to comfortable living room air conditions. BBS especially has a damping effect on the peak values of the humidity in the rooms. 1 m3 BBS stores approx. 7 litres of water with a room temperature of 20°C and an increase in the relative humidity from 55% to 65%. If the relative humidity changes from 80% to 55%, 1 m3 BBS gives off approx. 9 litres of water to the air in the room. As a building material, BBS will not be damaged during all of these procedures, has a damping effect on fluctuations in the humidity, and therefore balances the present room air conditions.

Binder cross laminated timber BBS Air temperature = 20° C
relative humidity	Moisture in wood	Water content
[%]	[%]	[l/m³]
80	~16	~ 69
65	~12	~ 50
55	~ 8	~ 43