Mass Timber in construction is here to stay and we are excited for the opportunities in sustainability and local sourcing that it offers our clients and the built world at large. At WALSH, we have fast become experts in this product type with several successful projects under our belt. Yet, we also recognize there is more to learn and we are constantly seeking new information, innovative mass timber uses, and collaborating with project partners to expand our resources. As members of the Tall Wood Institute’s REACTS Consortium and the Carbon Leadership Forum, our teams are staying on top of important bodies of research and advancing the uses for mass timber products.
Mass timber is a product type that includes cross-laminated timber (CLT), nail-laminated timber (NLT), dowel-laminated timber (DLT), glue-laminated timber (glulam or GLT), and some types of structural composite lumber (SCL). In addition, mass plywood and heavy timber fit the bill. CLT has become more popular of late and is produced by layering up many slices of wood at right angles and gluing them together, while glulam is manufactured in a similar way, but with slices all laid in the same direction. However they are used, mass timber provides a stronger, longer lasting and more environmentally-conscious alternative. Also, on average, a mass timber building is constructed 25% faster than a similar concrete building, according to Think Wood.
Embracing mass timber builds on our tradition of utilizing local, sustainably-sourced wood products, exemplified by some of our early projects like the Skamania Lodge back in 1993 which incorporated recycled, 100-year-old heavy timbers from an abandoned factory and salvaged wood flooring. A technology that has been embraced for over 20 years in Europe, mass timber is gaining momentum in the U.S. with Oregon and Washington leading the charge. WALSH is excited to be right in the middle of this effort.
Below, we’ve selected a few of our recent projects to share how mass timber was utilized in their construction:
PAE LIVING BUILDING
Located at SW First and Pine in the heart of the city’s historic Skidmore/Old Town District, the mixed-use PAE Living Building is the first fully certified Living Building in Portland and the largest commercial Living Building in the world. Using Douglas Fir as the mass timber of choice, the project placed it in the gravity frame, glulam beams, columns and Cross Laminated Timber (CLT) floor framing. CLT-5 spans over the top of the glulam beams and there is a 3.5” concrete toppings slab which acts as the floor diaphragm and also contains radiant heat. Built to last for 500 years , the building was designed to achieve level four (the highest level) of seismic resilience, allowing the structure to be habitable following a 9.0 magnitude earthquake. The building is also set to help achieve Portland’s 2050 renewable energy target of 100% renewable energy 30 years ahead of schedule.
Meyer Memorial Trust
Meyer Memorial Trust’s new multiple-award-winning Portland headquarters is a three-story, 20,000-square-foot building which achieved LEED v4 Platinum certification and is enrolled in the Path to Net Zero program, offered by the Energy Trust of Oregon. The campus offers employees many amenities—a library, educational garden, meeting spaces, and a roof top gathering space. A sloping roofline is one of the building’s most visible attributes, shaped to optimize solar access for a 50kW photovoltaic array, which serves to reduce the building’s energy needs by 30%.
While the office zone features traditional stick-frame construction, the event center is made of locally-sourced mass timber. The regionally harvested and locally manufactured mass plywood was selected for columns, beams and decking. This was done in order to highlight the beauty of this innovative industrial material and support the local rural economy. An added benefit was the opportunity to decrease the embodied carbon footprint of the building by reducing the amount of fuel needed to transport the materials to the site. Additionally, structural plywood mullions were used in the center’s curtainwall system. Interior finishes include acoustical slats made of hemlock certified by the Forest Stewardship Council.
Framework
The Framework CLT Tower was predicted to be the tallest wood structure in the United States by owner Project^. Currently on hold for financial considerations, the project underwent four years of rigorous testing and review to gain a building permit from the City of Portland and the State of Oregon in 2019. The project was designed as a 10-story, CLT wood-framed structure. WALSH’s Preconstruction & CEDC Director, Mike Steffen, played a critical role in the review and permitting process. For the Framework tower, Lever Architecture chose CLT for floor slabs and a lateral-force-resisting system (LFRS), and glulam to make up the beams and columns. Set atop a reinforced concrete base, the wooden structure was planned to be covered in glass, wooden screens and hanging plants that would allow glimpses of the timber structure, and the mix of shops, offices and residences inside. This project was ground-breaking and though has not yet been built, provided information that will be useful in future endeavors.
Capitol Campus Childcare Center
WALSH and Mahlum Architects partnered to design and build a new childcare facility to serve State of Washington employees. The single-story, 9,600 square-foot building was built with an eco-friendly design that focuses on conserving resources, ensuring air and water quality and reducing waste. Housing six classrooms, a light duty commercial kitchen, and a nature-based playground, the facility achieved LEED Gold certification and includes locally sourced CLT roof panels, solar panels, and numerous other biophilic design elements to achieve environmental goals and create a nature-inspired play space for children.
United States Forest Service Wood Innovation Report
Perhaps the most in depth body of research we’ve completed to date comes from the United States Forest Service Wood Innovation Report: Multi-Story Mass Timber K-12 Schools. Completed in conjunction with Mahlum Architects, structural engineer Fast + Epp, mass timber supplier Vaagen Timbers, PAE Engineers and acoustical engineer Arup, the team selected Sequim School District as their “client”. Mahlum began down this road by asking some questions amongst themselves about why mass timber was not being utilized in the construction of K-12 schools in Washington State. Questions such as: “Was the lack of mass timber schools related to cost? Or structural design? Or maybe the concept of multi-story, mass timber K-12 schools is just too new and therefore perceived as too risky?”
Bringing on WALSH project manager, JJ Powell, and assembling the other team of experts, the report: “explores the use of mass timber to deliver exceptional K-12 educational spaces in Washington State that are cost-effective, resource efficient, and low carbon. The primary focus of the grant is to study the feasibility of tall, multi-story (up to 3-stories) classroom buildings in Washington State with applicability across the Pacific Northwest as well as other regions of the U.S.”
To read the entire report, click here.
As responsible stewards of our community and a company that lives it values, continuing to provide our clients the best quality, most cost-effective projects possible is at the heart of our operation. We seek to learn and improve with this in mind, while taking care of our earth. If you are curious about the viability of mass timber use in your next project, please reach out and we can talk you through it.