When you think of high-rise buildings, you probably don’t imagine wood as the weight-bearing material. But Washington recently approved a change in its building codes that will allow engineered mass timber in structures up to 18 stories tall. That’s three times as high as current code allows.
Proponents of the change point to projects in Europe and nearby British Columbia to reassure skeptics that mass timber construction is not only as safe or safer than concrete and steel in earthquakes and fires — it also can provide a warmer aesthetic and more efficient construction designs. And it offers the prospect of creating new jobs in rural areas, if the wood is grown and manufactured in the state.
“It reconnects Washington to its heritage, in the most high-tech possible way,” said Michelle Connor, the president and CEO of Forterra, a nonprofit that helped with lobbying efforts to get the code change approved.
She wants to see Washington on the forefront of a new wave of mass timber construction. She says the jobs created in rural areas would be the equivalent of high-tech jobs at Boeing. Mass timber plants typically manufacture thick wooden pieces that are pre-ordered and cut to fractions of an inch. They’re assembled at faraway construction sites, requiring precise engineering that can shave months off of project timelines on the construction sites.
“And our cities and towns using this product, providing employment opportunities that are value added in our rural communities — to me, that really speaks to the sustainability that wood can provide to the region,” Connor said.
And using more mass timber has the potential to help with a labor shortage seen on many urban construction sites, says Joe Mayo, an architect with Mahlum Architects in Seattle, who helped lobby for the code change and also wrote a book on the topic, "Solid Wood."
“Contractors are struggling to find enough people to build buildings, so there’s a really big push to say, 'how do we build more efficiently? Are there some techniques we can do?'” Mayo said.
He added that mass timber requires fewer hours on the job site, because so much is pre-fabricated at the mill. And for the busy urban areas where most of the construction is happening, that also means fewer disruptions and less traffic from construction equipment. Many of these benefits have been recently reported from a pilot project in Tacoma, the Brewery Blocks development.
“There’s fewer trucks on site and they’re just using basically drills to screw these buildings together, so there’s none of the really loud construction,” Mayo said. “There’s fewer workers on the site. It’s generally safer, there’s less truck traffic, there’s less noise.”
And Connor, from Forterra, says it also offers benefits for landscapes far outside the cities. She sees an opportunity for the timber community in Washington to see less of its product shipped overseas. Wood products such as cross-laminated timber could provide a market for harvest of smaller, less desirable trees and scrap from forests managed by the Department of Natural Resources, possibly generating revenue for thinning that could lower wildfire risk. And if the wood is responsibly harvested, mass timber can also reduce the carbon footprint of construction, Connor says.
All of this requires more demand for the product. Currently, mass timber projects have to get their materials from outside the state. But two plants are under construction and one expects to begin production early next year.
Washington's code change should take effect in late April. That would make the state one of the first in the nation to move forward with taller mass timber buildings. The rest of the U.S. is expected to follow in a couple of years. Canada and Europe already have them.