This research presents the findings of a study conducted by Luleå University of Technology (LTU) and Lund University (LTH) on the effect of edge treatment on the end grain of cross-laminated timber (CLT) elements. The objective of the study was to identify whether edge treatment influences the moisture performance and mould risk of CLT. The investigation was conducted through controlled laboratory studies, utilising standardised procedures. Specifically, the end grain of the CLT specimens was exposed to moisture by placing them in contact with a free water surface for 96 hours. Following this exposure, the specimens were dried under controlled conditions. X-ray computed tomography (CT) scanning was used to estimate the moisture content of the specimens and provide detailed spatial information about the moisture distribution within the wood. To further evaluate the effectiveness of edge treatment, the experimental moisture content assessments were compared to values by WUFI simulations. Additionally, annual data for the simulations were conducted using climate data from three different locations: Lund, Stockholm, and Borlänge. These simulations assessed the theoretical impact of edge treatment on mould risk under different climatic conditions. Results revealed that edge treatment has potential to reduce moisture content and mitigate mould risk in CLT elements. Experimentally assessed moisture content values were consistently lower in edge-treated specimens compared to untreated specimens. The calculations and simulations supported these findings, showing a distinct reduction in moisture accumulation and mould risk in edge-treated CLT elements. This study provides insights into the effect of edge treatment on the moisture performance and mould risk in CLT elements. The findings suggest that implementing appropriate edge treatment techniques can enhance the durability of CLT structures, particularly for worksites in regions where climatic conditions fluctuate over the course of construction. Further research and testing are warranted to explore additional factors influencing the effectiveness of edge treatment in CLT applications.