Joint sealing
With visible insulated LIGNATUR elements with little above-rafter insulation and ventilation the lower slat functions as a vapour barrier and the joints are sealed with the airtight sealing cord.
Water vapour (diffusion) resistance factor of spruce wood according to DIN 4108-4.
- μ = 40 [–] (depending on humidity of wood, the dryer the denser)
- water vapour diffusion equivalent air layer thickness sd = μ ∙ d [m] = 40 ∙ 0.031 = 1.24 m for lower slat ti = 31 mm of LIGNATUR element
Vertical sealing cords at the bearing details have to be attached on site. The details, shown on the left, have been tested at the ift Rosenheim and have successfully passed several blower door tests.
Further sealing work for air and wind-tight details, like for example the bearing cross to the element in direction of the bearing, has to be done on site. Accurate carrying out is only possible if it has been defined previously in the planning process.