Moisture risk assessment of cross-laminated timber walls: Perspectives on climate conditions and water vapor resistance performance of building materials

Cross-laminated timber (CLT), an engineering wood material prepared by bonding lamina in a vertical direction, is actively used in roofs, floors and shear walls of residential and commercial buildings, owing to its excellent structural stability, insulation performance, among other advantages. The building envelope, to which the wood-based material is applied, should be designed to prevent moisture problems. In this study, the ply-lam CLT with plywood was prepared, and its hygrothermal properties including the thermal conductivity, water vapor resistance factor, specific heat capacity, bulk density, and porosity were analyzed. A small-scale test demonstrates the feasibility of hygrothermal behavior evaluation of the wall with ply-lam CLT by numerical simulation. Moreover, the moisture risk of the ply-lam CLT house walls was evaluated by analyzing the climate conditions of 20 major cities in Korea. The moisture risk assessment results imply, that to ensure water stability, the envelope should be designed considering the type of insulation material, its hygrothermal properties, thickness, climate conditions of the area, etc.