Vejledning 3 - Isoleringssystemer / Kork fibre
Cork
Insulation made of natural materials
Cork insulation is made from the protective layer of the cork oak tree (quercus suber L.) which may be periodically removed from its trunk and branches to provide the raw material for cork products. During the production process, product is made from ground granulated cork expanded and bonded exclusively with its own natural binder exuded from cork cell walls by heating under pressure.
Typical final products are distributed in cork boards and granulated cork. The perforation and cutting can be done at the construction site without losing the thermal properties of the material. The review by Jelle (2011) defines typical values for the thermal conductivity of cork insulation as 0.04 – 0.05 W/(m K), while the reference standard EN 13170:2012 gives values of 0.039 – 0.041 W/(m K) for dry material at 10 °C. Cork can also be used together with the hydraulic lime or cement mortar, in that case the measured thermal conductivity is in the range of 0.04 – 0.08 W/(m K).