Wooden basements; hygrothermal performance analysis using in-field measurements and numerical simulations

Basements represent an essential component of modern building design, serving as foundational structures with multifaceted roles in both residential and commercial constructions. The use of wood as a natural and costeffective material for basement construction plays a significant role in shaping the future, demanding wellestablished concepts to ensure sustainability. This paper presents an investigation of the hygrothermal behavior of basements built with wood elements, utilizing a combined approach of in-field measurements and numerical simulations. The variations in the temperature and relative humidity in different parts of the construction are monitored through a full-year measuring campaign in a reference building located in Switzerland. The measured data are used to first, analyze the performance of the structure in real operative conditions, and second, to validate the numerical model employed for the long-term performance evaluation of the building. Further numerical simulations are carried out to examine the reaction of the construction to various critical conditions. The results of the in-field measurements and numerical simulations ensure the applicability of using wooden elements in the basement structure under the conditions investigated in this study. The results revealed that the wood moisture stays below 18% as the limiting value specified by the standards. It is also shown that the wooden basement examined in this research has a satisfactory long-term performance with no concerns regarding moisture-related issues in terms of wood decay and mold growth. The risk analysis also demonstrated that the impact of the high initial moisture in the wooden elements on the hygrothermal performance of the assembly is higher compared to the high moisture load in the indoor space and the presence of a moisture source in the cold side of the insulation layer. The outcomes of this study contribute to the advancement of sustainable building practices, enhancing energy efficiency, and improving the resilience of wooden basements.