Moisture Mitigation for Mass Timber at Timberview VIII Affordable Housing

Truebeck Construction, a large west coast general contractor, is responsible for building Timberview VIII, an 8-story mixed-use, multi-family development in Portland, OR.

Timberview VIII is special for many reasons. It is much-needed affordable housing for the community, it boasts a sustainable and energy-efficient design, and it also happens to be the tallest mass timber building in the state as of June 2024.

The Truebeck project team is passionate about ensuring every aspect of the building is delivered with exceptional quality according to best practices. As the project got underway, moisture mitigation for the construction materials and mass timber products came into laser focus, and the team tackled it head-on.

CHALLENGE:

The beautiful and sustainable design of Timberview VIII calls for its primary structure to be constructed of glulam columns and beams, and cross-laminated timber (CLT) floor/ceiling panels supported by steel brace frames. The project team had two main concerns. One, the Pacific Northwest’s temperature and humidity over the 12+ month project could slow the drying schedule for materials like paint, drywall, and gypcrete. Two, the climate conditions coupled with incoming moisture-latent materials could affect mass timber moisture content.

"We'll always plan accordingly for traditional construction materials that require dehumidification. But with the addition of mass timber, we wanted to go the extra mile to make sure that we delivered a quality product,” explained Jack Doman, Project Engineer for Truebeck. “Swings happen in the moisture content, but you never want to get too wet or too dry.”

Monitoring ambient humidity and the moisture content of the mass timber components would help the team better manage conditions and avoid issues. Over-drying the mass timber could lead to cracking, checking and delamination, whereas under-drying, or excessive moisture, could extend timelines and lead to staining and mold.

The team considered walking the building every day to manually record moisture content levels with handheld meters and adjust climate equipment accordingly. However, that approach would require a dedicated person, and be wrought with risk and inefficiency.  “It would have been a nightmare to have to do that manually across the entire building,” expressed Doman.

They quickly decided that an efficient moisture management plan was necessary to meet the schedule’s tight deadlines, protect building integrity, and achieve the overall success of the project.

SOLUTION:

Truebeck consulted Polygon on how to design a moisture mitigation strategy that met their specifications and budget, as well as the need to proactively monitor the mass timber materials according to industry standards.

“It was really important for us to work with a climate control partner who had mass timber experience,” explained Patrick Valdefiera, Project Manager at Truebeck. “It was critical to us and the owner to ensure we avoid any issues, especially with how much focus and community impact the project is yielding. It was clear we wanted to work with Polygon.”

The Polygon team scoped and engineered a solution capable of maintaining conditions of 65-75 degrees Fahrenheit and 45-55% relative humidity, as well as providing real-time moisture content tracking and documentation. Operation technicians installed a complete system comprised of:

• Twenty (20) ExactAire Multi Sensors with Wood Moisture Content probes – The sensors units measure ambient T/RH with continuous readings of moisture content.
• Climate control equipment with ExactAire Smart Control - The inherent design of the R-15,000 Desiccant Dehumidifier and two (2) Indirect Fired Heaters provides optimal drying performance and heat with the least energy consumed. When adding smart control, it operates only when conditions call for it, delivering deeper energy savings and a hands-free system.
• Dashboards and alerts – A customized dashboard of all measures is divided into key work zones and critical areas. SMS and email alerts provide instant notification of potential issues. 

In June 2024, the project team was preparing to start work on the external facade and needed the equipment to be removed and different equipment set up inside. Such a change could take up valuable time, inconvenience the job site, and leave the building vulnerable at a critical time. With gypcrete being poured over the next few weeks, moisture levels indoors would be elevated. “We were on an especially tight construction schedule, it was really important to get Polygon involved,” said Doman.

In response, Polygon devised a plan to re-route the duct and reposition the existing equipment.  This maintained the conditions, simplified the logistics, and gave access to subcontractors to keep the job on schedule. “The Polygon team has been very easy to work with, accommodating, and flexible within the schedule and project constraints,” said Valdefiera.

RESULTS:

The system delivers the conditions, data, and alerts needed to properly manage moisture for the buildings. The teams are working well together to minimize disruptions on-site and keep things moving toward completion. The visibility and continuous monitoring are giving Truebeck the information they need to mitigate any potential issues and ensure building integrity.

“We are tracking conditions every day,” said Doman. “I am closely watching humidity fluctuations in the building and planning ahead with activities to make sure things are trending down in an appropriate amount of time. That's the goal: make sure that there isn't a problem and if the data indicates there could be one in the future, we can minimize it ahead of time – before it impacts the project. I think everyone would be happy to have this data and information to manage their projects in this way.”

BENEFITS:

Efficient Approach- Digitizing the moisture reading and piping data to high-performance equipment eliminates manual processes and human error and reduces energy. It also provides a more comprehensive solution, linking conditions to climate control equipment.

Instant and Constant Visibility – Continuous monitoring of multiple zones and mass timber points provides a historical record of changes over time and vital information to manage daily activities and compress the schedule without compromising materials.

Peace of Mind – The project team and owner have increased confidence in the quality of the building, knowing conditions were properly managed and there is a partner with experience behind them.

“We have peace of mind that we were going to turn over a high-quality building to the owner and community at the end of the day,” shared Valdefiera.

For more information on how Polygon can support your next mass timber project, visit us at www.polygongroup.com/en-US/masstimber.

Thank you to the Truebeck Construction project team for their cooperation and feedback on this project. We are grateful to have clients who are exploring new ways to mitigate mass timber moisture risk. We learn more together every day.  To learn more about Truebeck Construction, visit https://www.truebeck.com/.

Timberview renderings are courtesy of Access Architecture.