Hygrothermal behaviour of straw bale walls: experimental tests and numerical analyses

Written by esba

Straw is an organic material with hygroscopic properties. The high capacity it has for storing moisture from the surroundings can furthermore influence the performance and lead to the possible degradation of the material.

The aim of this study was to assess the conductance C-value of a complex material such as straw. A climatic chamber was used to study a sample, which reproduces a traditional plastered straw bale wall. Tests were conducted under different boundary conditions, setting constant values for temperatures and relative humidity. The revision of the assessment’s results allowed the calculation of conductance and conductivity values under different conditions. A numerical model was then designed starting from the laboratory data, which was used to characterize material properties. The match between software simulations and laboratory analyses will be a starting point for further tests.

Determining the straw conductance C-value is a difficult task to achieve, due to the complexity and the unique properties of the material. In spite of all this, laboratory tests have shown encouraging results, which reflect the great potential of straw as a building material.


  1. Mesa, Alessandra
  2. Arenghi, Alberto

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.