UP STRAW Research report on thermal conductivity and water migration

Written by esba

The application of bio-based insulation materials like straw requires a value for its thermal conductivity. It’s a physical property of any material. According to its Greek symbol it’s also called lambda value. Taking into account all lambda values of all materials of a construction and its thicknesses, the thermal insulation of a building is calculated according to ISO 6946:2017 building components and building elements – thermal resistance and thermal transmittance – calculation methods. This calculation became more and more important during the last decades, for it demonstrates the performance of the thermal envelope of a building and thus the savings of heat energy obtained with it.

All bio-based material will degrade, if only conditions are suitable. In that respect, moisture is a key issue, because degradation will most usually not take place within a construction if it is and stays dry. Degradation requires a necessary amount of water in the construction. In order to describe moisture-proof constructions with straw insulation, conditions must be known in which moisture quantities that would provoke degradation do not occur. This has been achieved in ETA 17/247 combining values of building physics.

Author: Benediktinerabtei Plankstetten, Benedikt Kaesberg, 2020


About the author


The European Straw Building Association is an independent European association, devoid of any profit making motive. The object of the Association is to promote and develop the use of straw, as a sustainable way of building in all the senses of the term “sustainable”: renewable, ecological, healthy, energy and climate efficient, social and economic.
The Association is a federation composed of organisations and people particularly concerned with the use of straw in buildings.