Mass Timber to Be Recognized in Washington Code

That’s a big reason why the state recently adopted legislation designed to recognize mass timber products like CLT in the state building code. CLT and similar materials are composed of multiple layers of wood. They can replace concrete or steel as a structural material, and, depending on forestry practices, they may come with a lower carbon footprint.

Going above six stories with mass timber

The new Washington law is simple: it directs the state building code council to write rules governing the use of mass timber in building projects. How does that help? “One of the key areas our coalition has identified as a barrier is building codes,” explained Matt Ojala, director of government affairs at environmental nonprofit Forterra. Forterra leads a coalition of architects, universities, environmental groups, and others in support of mass-timber construction.

Although the 2015 International Building Code (IBC), the current law of the land in Washington, permits the use of mass timber for buildings up to six stories, “it doesn’t really allow for widespread use of CLT” because of the height limitation, according to Ojala.

An International Code Council ad hoc committee on “tall wood” is looking into new rules for mass timber in the IBC, but the changes, if any, won’t be adopted until 2021.

Under the new law, though, taller wood buildings could theoretically be approved in Washington sooner.

Where the rubber meets the code

That’s the hope of state Senator Marko Liisa, Democrat from the 21^st Legislative District, who sponsored the bill.

“We expect the building code council will create more applications for these products in taller buildings,” Liisa told BuildingGreen. “With the tech boom sweeping Seattle, it would be nice to see some of our homegrown natural resources that are less carbon intensive” being used in construction, he added.

Liisa said the potential value of mass timber first came to his attention when talking to the mayor of the town of Darrington. That conversation got him thinking about “rural economic development and what we could do to help small towns struggling to create jobs [and] participate in the prosperity we see in the broader Seattle region,” Liisa recalled. He said new technologies, along with code developments, could “potentially revolutionize demand” for timber and create “opportunities for manufacturing in rural areas.”

Two new manufacturers of CLT recently announced plans to build plants in eastern Washington, according to the Washington Forest Protection Association.

What about sustainable forestry?

As the trend toward tall wood continues and U.S. manufacturers come online, the question of how to ensure sustainable forestry practices remains open. “I think that is definitely the challenge with using more timber products,” Liisa said.

“That’s absolutely something we have to be thinking about,” agreed Ojala, who said discussions have begun between the forestry industry and environmental groups about how to manage the issues. “It’s something we’re looking forward to engaging in,” he said.

More on mass timber

Engineering a Wood Revolution

Would Wood Skyscrapers Improve Urban Sustainability?

New Options Emerging among Mass Timber Panels