－ 283 － 1. INTRODUCTION Moisture control has become a worldwide is- sue because building operations and con- struction practices have been changing (Künzel and Karagiozis, 2010). As the buildings have become larger and more airtight, the ventilation rate has decreased more, and the insufficient ventilation leads to moisture problems. Indoor humidity level is closely related to health prob- lems such as skin irritation and respiratory problems (Zhang and Yoshino, 2010). High hu- midity level can create stuffy odor in a house and a breeding ground for mold, mildew, dust mites, and bacteria, which are harmful to resi- dents’ health (Fang et al., 1998; Bornehag et al., 2004). It also affects the construction dura- bility as dry air makes furniture to shrink, J. Korean Wood Sci. Technol. 2016, 44(2): 283~293 pISSN: 1017-0715 eISSN: 2233-7180 http://dx.doi.org/DOI : 10.5658/WOOD.2016.44.2.283 Original Article Comparison of Hygrothermal Performance between Wood and Concrete Wall Structures using Simulation Program 1 Seulgi Yu 2 ⋅Seong Jin Chang 2 ⋅Yujin Kang 2 ⋅Sumin Kim 2,† ABSTRACT Owing to an increase in the air tightness of recent buildings, the natural ventilation rate was significantly lowered and the removal of accumulated moisture became difficult in these buildings. The hygrothermal performance of these buildings should be carefully considered to provide comfortable indoor environment by removing the moisture condensation risk and the mold growth potential. In this study, hygrothermal performance of two selected wall structures was investigated based on WUFI simulation program. The results displayed that the indoor temperature had impact on the moisture accumulation in the insulation layer for both modeled walls, showing that lower indoor temperature resulted in higher moisture accumulation, especially in the wood frame structure. Also, the yearly moisture accumulation profile exhibited a downward shift throughout the year by adding a vapour retarder with a lower sd-value. In addition, both of the two walls have condensation risk in winter, due to low temperature level. The wood frame structure has a bigger fluctuation and higher condensation risk than the concrete structure. Keywords : hygorthermal performance, indoor humidity, WUFI, condensation 1 Date Received February 4, 2016, Date Accepted March 15, 2016 2 Building Environment & Materials Lab, School of Architecture, Soongsil University, Seoul 06978, Republic of Korea † Corresponding author: Sumin Kim (e-mail: skim@ssu.ac.kr)