Moisture Distribution in Cross Laminated Timber (CLT) Made from Heat Treated Wood

Abstract Cross-laminated timber (CLT) panels are recognized as an engineered building product worldwide and, given that they are made from solid wood, they can absorb moisture from or emit moisture to their surrounding environment when placed in either wet or dry conditions. This absorption and desorption processes creates a moisture gradient in the wood material, causing stress. This study investigates the moisture distribution and gradients in the CLT panels made from fir wood layers that have been heat-treated at 170°C. The panels were subjected to wet-dry cycles (from relative humidity of 88% to 32% and then from 32% to 88%). The paired heat-treated CLT panels showed less moisture and more uniform moisture compared to the untreated panels, with a less uniform moisture distribution and different moisture pockets. The moisture gradients between the treated and untreated the CLT panels indicated that heat-treatment affected the moisture gradient change. The treated panels had lower moisture gradients than the untreated panels.