There are two points of view for the prevention design of moisture problem in the building insulated envelope. One is the strictly prevention of high moisture condition in the insulated wall cavity. The other one is the permission of short-term high moisture condition, condensation and high moisture content of the wooden material as long as keeping physical durability. If the later standpoint were chosen, the insulated envelope design of every variety for Japan would be possible. Nevertheless, there are no criteria to estimate the damage of physical durability of wood by the biological factors related high moisture condition. In the previous paper, we reported about the concept of the prevention design of moisture problem in the building insulated envelope and the relationships between water content and decay various woods under hygrothermal steady conditions. In this paper, the relationships between water content and decay of various woods under two kinds of hygrothermal transient conditions are shown.
