Developing a Novel 1D-HAM Numerical Modelling Tool for Assessing the Hygrothermal Properties of Cross-Laminated Timber (CLT) Including Adhesive Layers

Although cross-laminated timber (CLT) has been used in Europe since the early 1990s, the building material is relatively new in the North American market. CLT is an engineered wood product composed of dimensional lumber adhered in orthogonal layers. During service, CLT products are susceptible to moisture cycles which can lead to short-term performance and long-term durability issues. Numerical software packages such as WUFI are traditionally used to investigate the hygrothermal performance of CLT materials; however, these programs do not consider the impact of adhesive layers on air and moisture transfer. The purpose of this study is to develop and validate a novel 1D heat, air and moisture (HAM) numerical modelling tool that considers the impact of the adhesive layers on the moisture and air transfer in CLT. This paper establishes a novel methodology for the hygrothermal analysis of CLT products which includes the impact of adhesive layers. The methodology and model are validated using existing WUFI software and the simulation of CLT without adhesive layers. The results of the analysis show that the adhesive layers slow the rate of moisture transfer within the wood layers bounded by adhesives. Future research includes a study and analysis of the hygrothermal impact of adhesive layers in CLT in specific climate conditions as well as further validation of the model using laboratory and field testing.