Prefabrication of Fully Ecological, Membrane-Free Timber Constructions Through Digital Manufacturing Methods

Abstract

Timber frame construction offers the possibility of merging the supporting and insulating layer of a load-bearing element into a single plane. Common structural elements therefore consist of studs and beams, allowing to place the required building insulation in the resulting clearances. The inside and outside of the wood stud construction is then completely covered with OSB or plywood boards to create a shear-resistant wall panel. Condensate can form in the cavities of the timber framing, especially during heating periods. In conventional wood constructions, a vapor barrier made of petroleum-based materials is usually applied to prevent water vapor from penetrating the insulation level. If all layers of the construction are made of plant-based building materials, a cascading further use of the raw materials is possible after deconstruction.

The mentioned planking of the components with wood-based boards is, in principle, sufficiently diffusion-inhibiting. The main reason for the need for an additional vapor barrier is due to the manual trimming and butt jointing of the planking. Inaccuracies occur, which do not ensure the water vapor tightness of the structure. This paper shows how a digital design and manufacturing process can lead to the ability to produce a fully ecological, foil-free construction by means of dimensionally accurate and computer-aided design of panel joints and connections. The hygrothermal simulation of the construction was calculated with the software WUFI 2D. The study shows how this can make a substantial impact on the ecological impact, durability, reliability and the comfort of living spaces of modern timber structures.