A major challenge in mass timber construction is wetting during construction and entrapping water within finished assemblies where it has limited ability to dry out. This paper presents a moisture-monitoring and hygrothermal modeling case study of a large mass timber building exposed to considerable wetting events during construction. To assess biodegradation risk, the authors developed and calibrated a 2-D hygrothermal model using Delphin software with field moisture content measurements at different depths and locations in CLT panels. The model was used to assess various remedial efforts for drying. Modeling results showed that desiccated air has a greater impact on drying CLT panels at depth than heat alone. Simultaneous site interventions helped target potential drying interventions. The authors also used the model to assess the potential for drying the mass timber under partially removed concrete toppings. Model data and predictions for mold growth and wood decay are compared with field measurements and observations.
This paper was presented at the ASHRAE 2025 Buildings XVI Conference.