Assessment of hygrothermal performance of ply-lam CLT wall assemblies in a dry-winter humid continental climate region

As global efforts to reduce carbon emissions in the building sector continue to grow, mass timber construction has emerged as a sustainable alternative to traditional materials. However, the application of mass timber structures in regions with extreme seasonal variations, such as South Korea, presents unique challenges related to moisture accumulation, condensation risks, and mold growth. Despite the adoption of engineered wood products, South Korea lacks region-specific guidelines for building envelope design, leading to potential durability concerns when relying on foreign design standards. This study evaluates the hygrothermal performance of ply-lam CLT wall assemblies under South Korea's distinct climatic conditions, characterized by hot, humid summers and dry winters. Using WUFI-based simulations, the study examines condensation risk and mold growth risk across multiple climate zones and assesses potential mitigation strategies. Results indicate that moisture accumulation varies by region, with higher condensation risk and mold growth risk observed in Incheon and Chuncheon due to coastal humidity and colder inland temperatures, respectively. Among three tested improvement strategies, replacing wood siding with a high water vapor diffusion-resistant cladding system was the most effective in reducing moisture-related risks. While this study provides valuable insights into climate-adaptive mass timber design, it is limited by its reliance on simulations, lacking experimental validation. Future research should incorporate long-term field monitoring and empirical data to refine moisture control strategies. The findings contribute to the development of regionally optimized, durable, and energy-efficient timber buildings, ensuring their long-term viability in South Korea's evolving construction landscape.