On the feasibility of watertight face-sealed window-wall interfaces

Abstract

Watertightness is still a major source of concern in the performance of the building envelope. Even very small deficiencies can cause a significant amount of water leakage which may result in structural degradation or malfunctioning of the insulation. The risk of water infiltration is highest at joints between different building components and in particular at the window-wall interface due to the complexity of these joints. This paper focuses on the performance of different solutions to ensure the watertightness of the window-wall interface, e.g. self-adhesive foils, liquid applied coatings, prefabricated frames, self-expanding sealing strips. The performance of these solutions is evaluated for different wall assemblies, i.e. ETICS, masonry, structural insulated panels and wood-frame construction. Laboratory experiments were conducted on a full-scale test setup with a window of 1,01 m high and 0,56 m wide. Test results showed that it is not evident to obtain watertight face-sealed window-wall interfaces without an additional airtight layer or drainage possibilities. Water ingress was often recorded at lower pressure differences.