Meyer Memorial Trust Is Made With Mass Plywood Panels

There are many different ways to make mass timber. Cross-laminated timber (CLT), developed in Austria in the '90s, is perhaps the most well-known. But there is a new kid on the building block: mass plywood panels (MPP).

We have covered it before, noting Freres Lumber of Oregon, which used to make plywood in four-by-eight sheets three-fourths of an inch thick, forgot to turn off the machine and ended up with 12-by-48 sheets up to 2 feet thick. There are decades of experience making plywood in the northwest U.S., so it makes sense. I noted at the time: "I suspect that we are going to be seeing a lot of this MPP, and that it is going to give CLT a run for its money."

Lever Architecture is proving the point with the Meyer Memorial Trust building in Portland, Oregon. The Trust is "a private foundation that invests in organizations, communities, ideas, and efforts that contribute to a flourishing and equitable Oregon... The building program includes an engagement center for public programs, mission library, cafe-style event space and roof garden terrace, workspace for 50, meeting rooms, and coworking space for partners."

MPP and other kinds of wood are used beautifully throughout the building, but that big workspace is where it shines with what look like giant mass plywood portal frames forming the structure. Lever Architecture principal Jonathan Heppner answered some questions about the material:

Treehugger: What are the advantages of using MPP over other methods, such as glulam for beams or CLT for slabs?

Jonathan Heppner: Cost for MPP is lower than glulam beams and columns and CLT slabs of similar thicknesses. Manufacturers are capable of producing mass timber elements from fiber of smaller diameter trees and equal design values as glulam and CLT elements and can produce MPP from forests with lower rotation cycles than those used for the production of solid elements. There are a variety of potential ecological benefits if the harvest of smaller diameter trees is combined with the retention of older (30-60+-year-old) trees in the same stand. Forest diversity, increased (exponential) potential for later life carbon sequestration, and improved ability to naturally respond to wildfires are among the positive benefits of retaining older (40-100-year-old) trees. 

In a fire, does it char like CLT where there is a burn layer designed in? Or does it burn differently because of the thin layers? 

MPP performs as well or better than CLT in a fire. Testing has been performed for 6-inch MPP panels to achieve 2-hour fire protection. There are differences in the performance between CLT and MPP related to how delamination occurs. CLT experiences fall off of char as the thicker lamella [layer] burn. MPP is denser and the charring and delamination are more consistent with thinner layers.

You pioneered MPP with Freres, but are others using it now? Is this going to give the Austrians and their CLT tech a run for their money? 

LEVER is not the only firm pursuing projects with Mass Plywood. A new extension to the Portland Airport (TCORE) by ZGF Architects is utilizing mass plywood at a grand scale for exposed long-span beams. Given its structural and fire performance characteristics mass plywood could be utilized in high-rise construction under the Type IV code provisions for mass timber to 12 stories and 180 feet. Given the right opportunity, I am sure it could be proven to provide the required 3-hour protection ratings for taller 18 story (max 270ft) high-rise towers, the maximum of what current Type IV code requirements would allow.

CLT isn't going away anytime soon, and MPP wouldn't be able to replace it. The appearances between the two can be a differentiator, from an aesthetic standpoint. Depending on where the project exists in the world, MPP might not be the most cost-effective option from a transportations standpoint. We view both as potential tools in our kit. We select the best fit based on performance, budget, appearance, social, and/or ecological benefit based on the unique characteristics of each project and the ability of either to best reinforce the desired objectives. 

What is the building’s general structural system? Can you tell us a bit more about the mass timber aspect of the project? 

The structure is traditional stick frame except at the convening space and pre-function spaces. The structure in those sections of the building is mass timber, specifically mass plywood. The green roof deck, beam, and columns are all exposed mass plywood. Additionally, the curtainwall system has structural mass plywood mullions. The interior mullions support the roof of the pre-function space as well as the 2 floors above it. The mass plywood panels are a local product by Freres Lumber, an Oregon manufacturer about 1 hour south of Portland. Mass plywood was selected to highlight the beauty of this innovative industrial material, support our local rural economy and decrease the embodied carbon footprint of the building by reducing the amount of fuel needed to transport the materials to the site.

This Treehugger tends to get carried away with the trees, but Heppner tells Treehugger there are other sustainable features in the building.

"The project connects sustainable building design with social equity and community development, demonstrating the synergistic relationship that can be developed between these goals," says Heppner. "In line with environmental objectives, the project achieved LEED v4 Platinum certification and is enrolled in the Path to Net Zero with Energy Trust of Oregon. The design for the new headquarters employs a number of strategies to achieve these ambitious certifications, including solar PV panels, an energy-efficient building enclosure, and HVAC system, on-site stormwater management, regional materials, and native plantings."

He adds: "The building uses 30% less energy and with the 50 kilowatt solar array, consumes 50% less energy when compared to a conventional code structure in Oregon. The building uses 35% less water indoors and 80% less water for irrigation. A dynamic filtration system and activated carbon filter media reduce air particulates, eliminate odors from entering the building, and create healthier indoor air quality for staff and visitors alike."  

Plywood is wonderful stuff. A few years ago I wrote that it's time for a plywood design renaissance. Years ago I wrote in "Plywood Homes Were Lighter and Cheaper, and You Could Build Them Yourself" that "good old plywood doesn't get the love that CLT or LVL (laminated veneer lumber) gets" and "perhaps it should be renamed with a cute anagram, say CLV for cross-laminated veneer."

And now we have MPP, which works for me. It's gorgeous stuff, and Lever Architecture has shown it at its best.