Moisture equilibrium in straw bale walls

Straw bales technology for buildings is developing in Belgium as in many other countries. The market is growing but significant uncertainties are left concerning how to model its dynamical hygrothermal performances and its long term behaviour. The present paper presents the preliminary analysis conducted on material parameters and component’s response to dynamic heat and moisture solicitations. The simulations use WUFI Pro software based on material parameters form literature and both reference climate files for Belgium and theoretical climates to analyse the interactions between straw bale walls and finishing materials and their influence on component performances and durability. A specific prefabricated wall element sold on Belgian market is detailed and introduced in simulations. The influence on comfort feelings and indoor air quality are discussed with a focus on component´s thermal inertia and moisture regulation capacity. The paper concludes with recommendations on wall composition to help straw bale technologies to develop in building market of Belgium and other countries.