wooden construction wall with clay

Important results from the project

The goal of the project was to investigate the possibilities of replacing glass and stone wool insulation and gypsum board in a wooden frame construction with bio-based insulation and clay board and thus expand the palette of climate-smart construction solutions. The biggest uncertainty concerned fire resistance and the fire test passed 114 min regarding load-bearing capacity, insulation and integrity (tightness). Clay boards are a hygroscopic material that has the ability to both absorb and release moisture to the surroundings and contributes to a positive indoor climate.

Expected long term effects

The critical moisture condition is between, 75-80%. The fire test passed 114 min and reaches a classification of REI90. Based on the results, the wall construction is deemed to be usable in a number of private homes and public premises. The assessment is that the project has contributed to another construction solution that can be used to minimize the climate impact of building materials. The clay board´s limitation is its sensitivity to mechanical impact, so it is best suited in private and office environments.

Approach and implementation

The task has consisted of evaluating the function of clay boards and building construction solutions according to Swedish standards. Tests have been carried out to verify fire properties and critical moisture condition. Properties such as insulating ability, tightness, acoustics and impact on the indoor environment have been assessed with the help of literature and previous studies. Göteborg Stad has led the project, the construction and participated in the development of the type wall. Claytec has contributed material. RISE has carried out the tests and assessed the properties.