The research project “Structural Timber Fabric: Applying Textile Principles on Building Scale” follows an innovative and experimental approach to develop novel lightweight timber structures. It examines structural and aesthetic qualities of textiles and textile techniques to assess their potential for large-scale application. From a structural-engineering point of view, the system-effect inherent to textiles is of special interest: textiles are made up of a multitude of elements that work together as one coherent structure. Failure of one or several elements does not entail the global failure of the structure. In addition to this technical advantage, from an aesthetic point of view, the application of textile principles at the building scale holds out the prospect of generating aesthetically outstanding timber structures. The visually appealing patterns that can be generated with such techniques are virtually limitless, and could increase the incentive for sustainable construction with timber. But the importance of timber for this research goes beyond its qualities as a renewable resource. Exploitation of its mechanical properties is a prerequisite for the structural system that it is the goal to develop. Furthermore, the usage of timber for structural fabrics makes sense from a conceptual point of view: textile fabrics are fibre-based systems, and timber is a fibre-based material. Based on the above starting assumptions, the research methodology relies on an iterative process of reciprocal exchange between theoretical knowledge and insights gained from practical studies of physical models and prototypes. An important achievement, the development of the Textile Module, results from this approach. This textile module can be summarized as an arch-like structural unit that consists of two interlaced timber panel stripes. This paper will focus on current problems of the research which deal with the question of how different Timberfabric structures based on a multitude of Textile Modules can be generated. In this context, double-layered build-ups are proposed, which are not only lightweight but also light-transmissive (see Fig. 1). Several recently developed examples of double-layered build-ups will be discussed in detail.