Hygrothermal performance of a new light gauge steel-framed envelope system

Hygrothermal performance of a new light gauge steel-framed building envelope system has been analyzed using three-dimensional thermal simulations, two-dimensional combined heat, air, and moisture transfer simulations, laboratory testing in a calibrated and guarded hot box (ISO 8990), weather resistance tests for full-sized structures, and corrosion tests and field measurements at experimental buildings in Ylojarvi, central Finland. The results show that a modern steel wall structure based on perforated steel studs performs satisfactorily in the cold climate at Finland. The perforations significantly reduce heat loss along the web of the profile. The field measurements show that no condensation has occurred in the frame system. Temperature measurements and infrared surveys in demonstration buildings show that temperatures on the inner surface of the wall are sufficiently high to prevent surface condensation or even increased surface humidity that could cause mold growth on the surface. According to the calculations, there are no corrosion risks in the steel frames during their estimated service life in the Finnish climate. The climate, however, has an important effect on performance, and the structures should be designed with regard to climatic conditions.