The effects of increased thermal insulation in timbre-framed external walls with a thin gypsum board as a wind barrier

Climate change and the need for energy savings challenge the hygrothermal performance of timbre-framed wall structures in cold climates. The future climate conditions will be more suitable for mould growth than the present, and the attempts to save heating energy involve the use of very effective thermal insulation. Hence, the hygrothermal performance of the outer parts of exterior walls must be studied and effective measures must be introduced to prevent mould growth. In this study, four timbre-framed exterior wall constructions were studied. All the walls were equipped with a gypsum board wind barrier having a minimal thermal resistance. Insulation thicknesses of 150 and 300 mm, demonstrating a moderate and a very effective levels of thermal insulation, were compared. Wooden cladding and brick veneer were compared as façade materials. Thickness of thermal insulation was the dominant parameter in this study. Although even the walls with 300 mm thermal insulation performed decently in the study, they might become problematic in the future. A wind barrier with a noticeable thermal resistance or the use of a thermal insulation layer outside the gypsum board wind barrier would obviously improve the performance of the studied walls.