The briefing for the research work under consideration was to establish design principles for windows, doors and facade elements in composite materials and timber. It was hoped that the use of composite materials would make it possible to improve the following key aspects of windows, facades and doors: suitability for a wider range of applications, improved commercial viability, longer service life, reduced maintenance input and longer maintenance intervals, using the diverse characteristics of Wood for improving aesthetic qualities, reducing heat losses by integrating insulation materials into frames as well as durability and sustainability of the products using renewable raw materials. The briefing of this sub-project 20 was to investigate various materials, types and design details of composites and report on the conditions under which these would be suitable as frame members or panels/boards in external wall applications. In combination with the results gained in sub-project 19 (design principles for window, door and facade elements made from
composites and timber; Future timber construction) as regards the exposure to moisture and the deformation behaviour of composite materials, the findings are a basis for further developments of material composites for window and facade construction.