Airtightness of the window-wall interface in wood-frame walls

Due to the increased focus on airtightness in the current building practice, a better understanding of air leakage rates through different building components and building interfaces is required. This paper investigates the airtightness of the window-wall interface in wood-frame constructions through a literature review and experimental study. Different wall setups, window installation methods and air sealing solutions were tested resulting in 20 different configurations. Air leakages rates ranging from 0.00 up to 3.66 m3/h.m at 50 Pa are measured and recommended configurations and installation techniques are discussed. The results show that a passive house level airtightness is achievable when using spray-in-place polyurethane foam or airtight membranes, if some general guidelines are followed.