Mass timber is not an entirely new concept. In fact, Europe and Australia started using the material in the '90s, and since then, it has slowly made its way to the U.S. What is so special about mass timber, and what role does it play in sustainable building?
What Is Mass Timber Construction and What Are the Benefits?
Mass timber products are constructed of thick, compressed layers of solid wood. Once bound, the load-bearing panels are strong enough for structural uses in commercial buildings and can even replace steel and concrete.
The materials commonly used in mass timber building construction are cross-laminated timber (CLT), glue-laminated timber (Glulam), dowel-laminated timber (DLT), nail-laminated timber (NLT), and structural composite timber (SCL). Like other prefabricated materials, these products are manufactured off-site and shipped ready to install.
In addition to being structurally strong, mass timber’s warm and natural finish makes it suitable for interior use. “There’s obviously a sustainability component to why people choose this material,” says Chase Gibbs, a project executive at Mortenson. “But mass timber has also increased in popularity because people like the feel of the product. It’s different from other materials traditionally used in construction.”
This desire to create healthier, more inviting interiors is all part of biophilic design—a trend spanning every market to help connect building visitors with the natural environment. Mass timber is an ideal material because it introduces natural, warm elements to spaces, but with a reduced environmental impact due to the sustainable methods used to grow, harvest, and produce the material.
How Mass Timber Fits into Sustainability Initiatives
Sustainability initiatives for commercial buildings previously focused on energy efficiency. Now, people are also looking at construction materials and a building’s long-term impact on the environment. As a low-carbon material, mass timber can help reduce a building’s carbon footprint over its lifecycle. But how exactly do you track that? It all starts with analyzing embodied carbon, which is defined by the United States Environmental Agency (EPA) as “the amount of greenhouse gas emissions associated with the upstream stages of a product’s life.”
Julianne Laue, director of building performance at Mortenson says, “Performing continuous embodied carbon modeling helps ensure you achieve sustainability goals by identifying, measuring, and analyzing embodied carbon in your building materials. We’ve found that looking holistically at the entire building helps you identify areas you might not suspect would have higher levels of embodied carbon, like insulation or vapor barriers.”
For these reasons, it’s critical to have a project team experienced in sustainable construction. Architects, engineers, and builders should collaborate in finalizing the design of the building, finding ways to incorporate low-carbon materials before a shovel even hits the ground. “You need all of it to work together to be successful, and for everyone to be on the same page in terms of your sustainability goals,” says Julianne. “Early team involvement guides procurement and estimating to ensure materials selected help rather than hurt the chances of receiving sustainability certifications.”
The Role of Transportation in Sustainability
Sustainability is about more than the materials chosen for a project. To keep a mass timber building’s carbon footprint as small as possible, you need to consider where you source the materials and how they’re transported from point A to point B.
“Transportation impact is a major consideration in using mass timber,” says Julianne. “That’s why part of Mortenson’s carbon modeling process involves analyzing the impact of shipping the mass timber from overseas versus sourcing and transporting it from the U.S.”
“Several factors go into that analysis too,” adds Chase. “For example, having 15 out of 12,000 containers on a ship that is already coming overseas has less impact than hiring a separate vessel for a small overseas shipment.”
Project Spotlight: Sustainable Mass Timber Building in Action
As a versatile and structurally stable material, mass timber works across a range of markets. Here are a few mass timber buildings combining style and sustainability.
The Beam on Farmer® in Tempe, Arizona sets the gold standard for mass timber and sustainable construction.
The Beam on Farmer® is Arizona’s first cross-laminated timber class-A office building. The five-story, 184,000-square-foot award-winning building leverages the beauty and structural strength of mass timber with 13-foot exposed wood ceilings and glulam beams and columns. The large grid spacing and high exposed ceilings allowed for maximum interior design flexibility to create a modern, urban office atmosphere.
Blake Early Learning Center in Hopkins, Minnesota blends sustainability with a modern aesthetic.
Blake School Early Learning Center is a 36,000-square-foot, 2.5-story elementary school in Minnesota. The glulam-framed mass timber construction was part of larger sustainability goals to reduce energy consumption and the impact on our climate and environment—including a geothermal heating and cooling system and renewable energy sources. The tall, exposed ceilings pair with large windows to introduce natural elements to learning spaces.
Kaiser Borsari Hall is a 54,000-square-foot, four-story mass timber building currently under construction at Western Washington University. Exposed Glulam columns tie in natural elements found in the forest surrounding the building. The design also incorporated cross-laminated timber (CLT) decks as part of the University’s goal of achieving International Living Future Institute (ILFI) Zero Carbon and Zero Energy Certification and being the first carbon-neutral collegiate facility in Washington.
Getting Your Mass Timber Building Construction Off on The Right Start
There are many things to consider when incorporating mass timber into a design. A structural engineer is one of the first team members to enlist before planning the design. Together with the architect and builder, they will ensure you meet sustainability and design goals while ensuring a structurally sound building.
“Aesthetics are another big thing,” says Julianne. “You have all of this beautiful wood throughout the building, and you don’t want to ruin that aesthetic with ducts, cables, and other electric and mechanical components.” Engaging a mechanical, electrical, and plumbing (MEP) engineer will help your design team plan around these systems and find creative ways to integrate them so the material can shine. For example, The Beam on Farmer® design incorporated a raised floor, allowing for underfloor cabling, wiring, and air distribution systems instead of housing everything in the ceiling. Of course, there’s an additional cost associated with these unique approaches, so that is always a consideration for budgets.
With so many factors to consider, you need a team experienced in mass timber construction and project planning. “We’ve learned a lot about the design risks and mitigation opportunities associated with mass timber projects,” says Chase. “Each situation is different. You need a team with the right resources, research, and expertise to determine the best, most efficient way to build with minimal risk to the customer.”
Learn more about sustainable construction
Kelly Ontiveros
Project Manager, Mortenson
Kelly has been in the construction industry for nearly 25 years, bringing thoughtful leadership to projects while cultivating trusting relationships with customers and partners. Her recent experience building The Blake School's Early Learning Center will provide insight into lessons learned as she guides the discussion for our panel of experts.
Julianne Laue
Director of Building Performance, Mortenson
With over 25 years of experience in sustainable design, operations, and construction, Julianne drives Mortenson’s sustainability practice, specializing in energy efficiency analysis, building physics, life cycle cost analysis, and carbon reduction. Julianne is also experienced in design and simulation of whole building integrated systems and provides strategic advice on a wide variety of building types and scales.