The arched roof is composed of four wooden elements which are connected by a ring anchor to the outer walls. It is created by means of a mesh of combed Kvh 40/60 wood in a 30 x 30 cm grid. A cross-shaped screwed roof formwork of smooth edge boards 18/95 mm gives the roof construction the necessary strength. A second under-ventilated wood formwork with bitumen sheet sealing protects the insulation layer from the weather.
All exterior surfaces of the building are diffusion-free and allow for an all-round exchange of air and gas. The building materials are wood, clay and hemp. Metals have only been used as screws and hinges.