Abstract
An experimental straw bale structure at Nihon University's Center for Natural Environmental Sciences, called “ Atom House ” , is the first straw bale building constructed for research purposes in Japan. Construction began in 2002 and was completed in 2006. Indoor, outdoor, and interstitial hygrothermal conditions have been monitored since December, 2002. The present study describes the hygrothermal monitoring and evaluates Atom House on two levels: (one) Atom House's thermal performance and (two) the interstitial hygrothermal environment and potential for mold growth. Although the indoor environment is unconditioned, indoor and interstitial temperatures are moderate in comparison to outdoor temperatures, providing evidence for the insulative quality of straw bale walls. Evaluation of the interstitial hygrothermal data using an isopleth model predicts fungal growth within the straw bale walls. Extraction and magnification of straw confirms the presence of mold and the need to control interstitial moisture in straw bale walls.
