Wood fibre insulation and straw bales

The challenge

Design an addition to a restored old farm house. Previous experience with the farm house restoration, using woodfibre insulation boards, earthen plaster and radiant wall heating convinced the client to implement the same materials in the addition’s design. For both the restoration and the addition, the client desired healthy building materials that were ecologically safe and would not produce hazardous emissions.

Our solution

A structural system comprising a frame constructed from prefabricated I-joists, used as studs/posts, with straw bales to fill the cavities between the uprights. GUTEX Thermowall external thermal insulation composite system, 40-mm thick, including a mineral render, covers the straw bale walls. The roof insulation consists of GUTEX Thermofibre blow-in woodfibre insulation with GUTEX Multiplex-top used for the sheathing. The interior walls are also filled with blow-in woodfibre insulation.

Project features

  • Half-timbered house and new addition share a pellet furnace (15 kW) that furnishes the primary heating (heat lines installed in wall plaster).
  • In addition, each building has its own masonry heater.
  • Living area of new addition is 110 m².
  • Primary energy source usage (as per EnEV abbr.: QP): 22.83 KWh/ m² annually.
  • Roof U-factor = 0.165 W/m²K.
  • Wall U-factor = 0.115 W/m²K.

Construction solutions

Would you like to see the construction details? You'll find similar constructions described here.