Moisture monitoring for timber durability research

Université Laval conducted a durability study for Parc du Massif du Sud, in collaboration with Goodfellow and Latéral, to evaluate the performance of various coating and protection systems applied to hybrid glued-laminated timber (glulam) beams intended for exterior exposure.

Led by Professor of Timber Engineering Alexander Salenikovich, eng., Ph. D., alongside Master’s Student Coralie Offroy, the two-month research program compared different wood coatings by monitoring moisture content, modulus of elasticity (MOE), and visible signs of deterioration under cyclic environmental conditions simulating accelerated exterior exposure. The objective was to evaluate the coatings’ effectiveness in enhancing timber durability and long-term performance.

CHALLENGE

The Université Laval research team required continuous and accurate moisture monitoring throughout a durability study conducted for Parc du Massif du Sud. The study involved twelve hybrid glued-laminated timber (glulam) beams composed of a Douglas fir-larch structural core and sacrificial Western Red Cedar laminations. Four test groups were established to compare the effects of sacrificial lamination thickness and protective coating systems under alternating wet and dry climate cycles inside a controlled conditioning chamber. 

The applied cycles consisted of an 8-hour wet phase at 95% relative humidity and 25°C, followed by a 16-hour dry phase at 40% relative humidity and 40°C. Researchers aimed to evaluate potential delamination in glued interfaces or any surface checking and cracking, monitor changes in the beams’ apparent modulus of elasticity (MOE) under varying climate conditions, and compare the performance of different coating systems and sacrificial layer configurations.

To better understand how moisture fluctuations impacted the beams throughout the testing process,
the team needed a reliable way to continuously monitor internal wood moisture conditions.

SOLUTION

Université Laval connected with Polygon during the planning phase of the project, allowing continuous monitoring to be integrated into the study from the beginning rather than relying on conventional manual measurements using pins or standalone data loggers. Polygon provided 12 Multi Sensors to continuously monitor internal wood moisture conditions throughout the environmental conditioning cycles. The sensors were installed approximately 32 millimeters into each beam at a location 16 inches (406 mm) from the beam end, allowing them to capture moisture behavior from within the timber rather than relying only on surface-level or periodic manual readings.

“Without the Polygon Multi Sensors, we likely would have relied on standalone data loggers and periodic manual moisture measurements,” explained Coralie Offroy, Master’s Student at Université Laval.

Over the two-month testing period, the sensors continuously recorded humidity conditions while the Université Laval team carried out repeated modulus of elasticity testing and mass measurements at different stages throughout the experiment. Together, these data points helped researchers compare how the different coating systems and sacrificial layer configurations performed under simulated exterior conditions.

Polygon’s online user interface provided real-time visibility into sensor activity through dashboards and alerts, making it easy to review measurements throughout the study.

“The dashboards allowed real-time verification of sensor operation at any moment during the experimental program.”

By accessing the data, researchers could quickly visualize sensor readings and short-term trends for each beam through graphical displays showing temperature and humidity variations over previous days. This visibility allowed the team to track evolving conditions throughout the study and confirm that sensors were functioning properly during the entire monitoring period.

Throughout the project, Polygon also provided ongoing technical support and collaboration to help ensure the success of the monitoring program.

   “The communication and technical support provided throughout the project       were excellent,” added Offroy. “The collaboration with Polygon contributed         positively to the success of the project.”

RESULTS

The continuous moisture monitoring data collected throughout the study helped researchers evaluate the performance of different coating systems and sacrificial layer configurations under simulated exterior exposure conditions. Key findings from the study included:

• All beam groups experienced progressively smaller moisture-content fluctuations over time and demonstrated an overall drying trend throughout the testing period.
• The drying trend was accompanied by a slight reduction in beam mass and a corresponding increase in apparent modulus of elasticity (MOE).
• Beams treated with additional coating systems showed smaller moisture-content fluctuations during the early stages of testing compared to untreated groups.
• The additional coating systems also resulted in fewer and less severe surface cracks, indicating improved protection against surface checking under cyclic environmental exposure.
• Overall, the additional coating systems provided measurable benefits in reducing surface checking and cracking, an important consideration for long-term outdoor timber applications.

Following the initial testing phase, Université Laval is continuing their research by placing beams outside under real exterior conditions. Four Multi Sensors are being used outdoors to monitor beam performance throughout the summer as part of the ongoing research program.

BENEFITS

• Improved Client Reporting: Use of sensors allowed Université Laval to collect and provide the continuous data necessary to support the research objectives and reporting requirements for Parc du Massif du Sud.
• Better Project Visibility: Continuous monitoring provided higher-resolution data compared to periodic manual readings, helping researchers better understand how moisture fluctuations impacted timber performance and durability.
• Trusted Collaboration: Responsive technical support and ongoing communication from the Polygon team helped ensure a smooth and successful monitoring process from installation through project completion.

Learn more about how Polygon can support your mass timber project with moisture management solutions, or contact our team to discuss your next project.