Evaluation of joining methods for novel timber–aluminum composite profiles for innovative louver windows and facade elements

The demand for efficient buildings requires improvement in window and facade design. Aluminum and steel dominate the solutions for large facades while wood is used on a much smaller scale. In order to widen the scope of wood application in facades, this paper assessed novel timber–aluminum composite profiles which have been developed for louver windows. The research focused on two different technologies suitable for joining wood to other parts of the louver window. First, the study assessed the adhesive bond between the glass unit and the wooden part of the profile. The evaluation focused on seven different wood substrates ranging from solid softwoods and hardwoods to wood-based products and modified wood. Second, a specific rolling technique was applied to join the wooden section to the aluminum component. The technology was taken from the prefabrication process of conventional composite profiles. There, plastic insulating bars are clamped onto the aluminum profiles. This joining method had not been applied to timber so far. The results show that beech wood has the most suitable properties for use in such composite profiles. The composite frames examined provide a lower energy footprint compared to standard solutions. They enable a sustainable yet durable solution for the building envelope.