Highly insulated wooden structures in Nordic climate

Since many years there are discussions in Nordic countries about the moisture behaviour of highly insulated wooden structures and fully insulated roof structures without ventilation gap. Moisture accumulation is feared, leading to possible mould problems in the structures. Actual simulation programmes like WUFI® [1] are not folly evaluated for the Nordic climate conditions and might not be accurate, hence they cannot reliably proof the operational reliability of the structures. Therefore three test houses were built at Aalto University to investigate the moisture and temperature behaviour of different wooden structures in the Southern Finnish climate. Measurements started in December 2011 for three different types of timber structures from lightweight to massive timber combined with various insulation materials and vapour resistances of the structures. The measured data was then compared to numerical WUFI® simulations.