The pilot is owned by:
The aim of the project
The pilot project in Sveabakken 13 consists of a flat compact, unventilated wooden roof with «smart» vapour barrier. The roof is built with I-profile wooden loadbearing beams with mineral wool insulation between the beams, roof fall insulation on top of the underlayer roof, and black asphalt roofing. The vapour barrier «DuPontTM AirGuard®Smart» (SINTEF Certification No. 20321) delivered by Isola is used.
NTNU and SINTEF have, in cooperation with Isola, conducted extensive calculations and laboratory tests on compact unventilated wooden roofs. The pilot project will demonstrate and document roof performance with a product type we consider ready for field testing.
Smart vapour barriers can vary the vapour resistance to what is actually needed. Physically, they operate so that at low relative humidity (RH) the vapour resistance is high, while when the RH increases, the vapour resistance decreases. In winter, when the RH in the indoor air is low, the vapour resistance will be large. And in summer, when the RH in the indoor air is higher, the vapour resistance will be lower.
For constructions with a limited possibility of drying outwards, and which contain moisture sensitive materials, drying out possibility to the indoor air is of particularly interest. Compact unventilated wooden roof is such a construction. This is a structure that have traditionally not been recommended though it is very economically interesting. The use of smart vapour barriers can thus be a cost-effective measure to improve climate robustness for compact roof structures.
Properly used, smart vapour barriers can provide more robust moisture protection and making the roof less vulnerable to increased rain load. The use of smart vapour barrier in roof constructions can reduce the build height (utilizing the distance between the beams for insulation), reduce material usage, give more efficient constructions and economical gain.