Maintenance Considerations for Mass Timber Construction Projects

3/18/2024

For all projects constructed of wood, a primary maintenance concern is the impact of moisture over long periods of time. According to Sullivan, an impenetrable envelope, in concert with a well-conditioned space, is critical for the longevity of mass timber, which can have a lifespan beyond 150 years (as exhibited in historic mill structures).  

“Additionally, mass timber projects are more quickly constructed, allowing these buildings to become watertight at a much earlier point in the construction process – when compared to steel and concrete framed buildings,” Sullivan says. “When completed, moisture levels can be monitored and mitigated with systems already utilized for most modern environments.”  

Additionally, if the mass timber elements are intended to interact directly with the exterior environment, special maintenance strategies should be considered. For fully-exposed elements, timber can be treated with a weather coating to enhance water resistance for softer wood species. These coatings, however, require ongoing maintenance in the form of incremental reapplication. In some cases, water treatment sealers have the potential to discolor the timber itself and impact its aesthetic integrity over time. 

Parsons agrees that moisture management is a key consideration in the use of mass timber products, which are primarily made to be used in interior and dry conditions, just like most structural wood products.   

“Decks for example are allowed to be exposed but structural wood is designed to stay dry. Proper detailing can help mitigate moisture,” Parsons says.  

As Sullivan further points out, traditional spray-on fireproofing (as you would see in steel construction), and its associated maintenance considerations, is not required for mass timber projects. Instead, fire resistance is inherent to mass timber construction, as its components are designed to be slightly oversized, taking into account the charring that would occur during a potential fire event.  

“When the structure is the architectural finish, it does take some planning during construction and then maintenance to understand how to care for the building,” Parsons says. “It can easily be planned for during design and a plan can be developed to keep the building looking great.”  

Related Content: Milwaukee to Feature World’s Tallest Mass Timber Building

Within life sciences facilities, architects often must accommodate complex and highly-specialized infrastructure. A primary consideration for Class A research space includes providing appropriate structural spans to support flexible and efficient lab layouts, while meeting the required floor loading and vibration control metrics needed to support a range of scientific processes. Additionally, pathways for exhaust, ventilation and specialty ductwork/piping must be accommodated to facilitate the diverse mission of each tenant.  

“Understanding how to implement mass timber to respond to these critical design drivers has been a common hurdle in the advancement of its implementation for life sciences developments,” Sullivan says. “However, through our extensive research, we’re confident that the pragmatic solutions proposed by our team of experts will remove these technical roadblocks. It's our aim to share these concepts with the broader design and construction industry to promote the use of mass timber and its associated benefits.” 

Parsons also says that the biggest challenge is having everyone around the design and construction table know about the mass timber products and how to design and build with them.   

“Education is a major hurdle with such a new system. In 2023, WoodWorks provided 79,000 hours of education,” Parsons says. “Our clients are very interested in understanding every aspect of mass timber and taller light frame buildings. Part of this awareness is everyone seeing what has been built already – nearly every part of the country has a mass timber building. The WoodWorks Innovation Network has a crowd-sourced map of built projects here.  

WoodWorks tracks the market in the United States and has seen a steady increase in the adoption of mass timber.  

“We believe that this momentum will continue as more people learn about mass timber and as more states adopt the tall wood code provisions,” Parsons says. “The next major tailwind in the mass timber market will be a broader understanding of embodied carbon of the built environment and that mass timber provides a major step forward in a sustainable future. Right now, the AEC (architecture, engineering and construction) community is building mass timber because it looks good and helps their jobs pencil out. The carbon understanding will help propel these technologies forward.” 

Maura Keller is a freelance writer from Plymouth, Minnesota.