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It’s being touted as a revolutionary new building product 鈥� an architect’s dream and the answer to two decades of job losses in the Oregon timber industry, with the potential to radically alter others.

But not everyone is over the moon over cross-laminated timber, or CLT. After all, wood isn’t the only building material on the market. Steel and concrete still dominate, and those industries aren’t about to give up market shares without a fight. Their representatives readily offered the 91视频 skeptical takes on the emerging mass timber product. They noted life safety issues as well as the public money going to develop and promote CLT, and took issue with some claims made by its supporters.

As building codes adapt and CLT’s supporters push for broader acceptance, a tough fight might lie ahead.

鈥淲hat we’re learning up here,鈥� said Bruce Chattin, head of the Washington Aggregates and Concrete Association, 鈥渋s that (CLT is) not ready for prime time.鈥�

Zeal of a convert

Even Oregon State University wood sciences professor Lech Muszynski admitted that when he first learned about CLT, in the mid-2000s, he was unimpressed.

鈥淎t first I thought, that’s a terrible idea,鈥� he said. 鈥淏ut gradually I grew more familiar with what is great about it, and I was converted to an enthusiast.鈥�

In the years since, Muszynski, born in Poland, has been enlisted to help spread that enthusiasm about the emerging building material. But as a non-native English speaker, he worries spokesman isn’t the most natural role for him.

鈥淚 would rather do the research,鈥� he says. 鈥淏ut I will talk.鈥�

At first glance, there’s nothing particularly new about CLT 鈥� engineered wood has been used as a structural building component for decades. But proponents like Muszynski and Ethan Martin of the Wood Products Council say CLT could be radically more effective.

鈥淭here’s potential here to disrupt several industries,鈥� Martin said.

CLT is made of dimensional lumber glued at right angles 鈥� big, sturdy panels that can be used as prefabricated wall, floor or roof elements 鈥� plywood on steroids, it’s been called. Because of its structural strength, there’s talk it can be applied to building projects where wood hasn’t traditionally been considered, including in manufacturing facilities and, notably in the Pacific Northwest, high-rises.

CLT panels arrive at a job site shaped precisely for use, with windows, doors and other elements pre-cut. At the site, they’re 鈥渟napped鈥� together like Ikea furniture, Muszynski says. This sort of prefab customization can significantly reduce project time and cost. One floor can go up in about a week, instead of two to three using more traditional building methods. Because of this, CLT has earned the attention of leading building firms, for whom time is as good as money.

Architects have also taken note. Modern buildings have traditionally hidden their load-bearing elements. But among designers in Portland, wood is considered a handsome substance, and many are apparently eager to show it off. In the creative field of architecture, innovation is key, and it’s always good to have another tool in the toolkit.

Another presumed benefit of CLT is in providing a purpose for beetle-killed lumber and 鈥� possibly, though it’s not known for sure 鈥� small-diameter logs removed during fire prevention and forest restoration operations.

Right now, Portland has more CLT structures in development than anywhere else in the country, including what will be the tallest CLT building in the U.S. (the 12-story Framework building), and the first one to use U.S.-sourced CLT panels (Albina Yard). The state government has allowed scheduled updates to the International Building Code to go forward a year early, giving Oregon a head start.

The Framework tower planned for Northwest 10th Avenue is the recipient of one-half of a $3 million prize by the U.S. Department of Agriculture for tall wood building designs. (Confusingly, another project in development in the Portland area also named Framework is employing mass timber 鈥� though not CLT.) The other tower that won USDA grant money is being developed in vertiginous, glass-and-steel Manhattan.

Muszynski’s expertise involves establishing lines of production. He’s so far helped set up the first and only full-scale commercial CLT manufacturing process in the U.S., at DR Johnson Lumber, a maker of glue-laminated beams in Riddle, south of Roseburg.

A number of Oregon institutions are working to accelerate broader adoption of CLT in the IBC, including OSU and the University of Oregon, and quasi-public organizations like the Wood Products Council’s WoodWorks group, Oregon BEST and the Oregon Forest Resources Institute (OFRI). They feel the state is uniquely positioned to become a hub for a domestic CLT industry. Their reasons include the state’s fertile timber lands, a community of progressive architects and engineers, a proximity to populous California and an easy link to overseas markets. And here in the Pacific Northwest exists the potential to revive flagging timber towns by adding jobs up and down the supply chain.

鈥淩ight now there’s a big push from architects to use this product; it’s an amazing looking product,鈥� Martin said. 鈥淭he downside? The downside is it’s a new product.鈥�

Caution and care

Substantive critiques of CLT break into three categories: seismic, fire and moisture/air quality. Critics note that with each, regulatory hurdles remain before CLT can be used in wider applications.

For one, performance factors for seismic testing must be devised and codes written according to geologic area. This is because Europe 鈥� where CLT was developed starting in the 1990s 鈥� isn’t nearly the seismic hot spot the Pacific Northwest is. In Europe north of Italy, very few seismic codes exist.

CLT is heavy and so stiff that it doesn’t flex as well as other wood, so it poses different challenges from a design standpoint.

鈥淢y primary concern as an architect and longtime building professional is life safety; that’s where the rubber meets the road,鈥� said Gregg Lewis, senior director of the National Ready Mixed Concrete Association. 鈥淐oncerns about safety are the number one issue that needs to be addressed 鈥� the rush to adopt new technology before adequate vetting has occurred seems to me short-sighted.鈥�

Lewis, a registered architect, said the architecture field’s constant quest for the next new thing is a good thing, but it can also be a liability.

鈥淲e want to push things forward from a design standpoint,鈥� he said, 鈥渂ut it has to be a matter of caution and care when we have people’s well-being in mind.鈥�

Said Aaron Blake, principal of Reworks Inc., contractor-owner for the Albina Yard project in North Portland: 鈥淐LT performs incredibly well in seismic tests.鈥�

The threat of fire in a wood-framed building seems obvious. In fact, it’s the reason behind the traditional four-story cap on wood-framed buildings. And proponents admit it’s still a considerable worry among the public.

Critics point out that five stories is about the level that most fire-fighting apparatuses can effectively reach.

Despite the existence of European research on fire performance, the lack of U.S.-based testing on U.S. products is also considered a barrier to CLT being approved in tall buildings in America. Muszynski is involved with research in this area that’s scheduled to conclude in 2018.

Supporters say, on the contrary, CLT provides excellent fire resistance. For those who need convincing, Muszynski has a photo showing the scorched bones of a building following a devastating fire, melted steel beams drooping limply over a charred, but stiff, wood beam.

Moisture is the problem that CLT’s supporters and critics seem to agree poses the greatest threat. The main difficulty here comes during the construction period, when projects are pelted by rain and moisture finds its way inside separations in the CLT panels. Along with structural issues, if water doesn’t dry properly, the resulting mold can lead to health issues for building occupants. Diligence is necessary to scrape off water that collects. Fans and well-placed holes also help.

A couple of CLT buildings in Vancouver, British Columbia, now face serious issues with moisture, according to Charles Kelly, president of the British Columbia Ready-Mixed Concrete Association.

Insuring CLT buildings has proven to be an issue in Canada as well, Lewis says.

While construction costs for CLT and other building materials are comparable, insuring a wood building 鈥� and especially with condos 鈥� is much higher due to moisture, he said.

鈥淭his is the principle problem with CLT, and it wouldn’t be a problem if we were only building in Texas,鈥� Lewis said. 鈥淭he insurance companies have much higher deductibles and higher rates for wood-framed buildings than they do for concrete buildings. It’s just the nature of wood 鈥� it’s not any more than that.鈥�

Lewis said little is known about how CLT performs, whereas concrete has been around for thousands of years.

He’s opposed to government 鈥渢ilting the playing field鈥� through support for CLT and other building products. Innovations in his industry, which range from translucent concrete to self-healing concrete to better performing concrete admixtures, rarely get a public boost.

Beyond practical concerns over the utility of CLT, its critics say it’s not cost-competitive, and has gotten an unfair push thanks to public money. The quasi-public organizations mentioned previously together have budgets totaling $10 million, with much of it last year going to CLT promotion. Oregon BEST is a quasi-public organization that last year used $6 million to fund and promote 鈥渃lean tech鈥� businesses and products. OFRI, with an annual budget of about $4 million, is funded by harvest tax dollars.

鈥淐oncrete’s not cute anymore,鈥� said Rich Angstrom of the Oregon Concrete and Aggregate Producers Association, and added, 鈥淚 think a lot of people are drinking the Kool-Aid.

It’s natural that CLT would cost a little more for a little while, said Timm Locke of the Oregon Forest Resources Institute.

鈥淭he very first iPhone wasn’t cheap,鈥� he said. 鈥淭he first concrete building probably wasn’t cheap.”

Consider the source

鈥淐ollectively, you have to think about the source of these criticisms,鈥� Locke said.

The building product most likely to be displaced by CLT is concrete.

The industries share the fact that they’re building materials. Their representatives actually agree on many legislative issues.

Another collaborative project involves a Canadian design contest that sought to use the 鈥渋nnovations鈥� section of the IBC. With a goal of using the right material for the job, the project team utilized concrete, steel and CLT to design an 18-story building. After some trial and error, concrete was settled on for the basement, stairwells and building core; CLT for the floors and wall separations; and steel for the building exterior.

An example of such collaboration is one put forward by Kelly of the BC Ready-Mixed Concrete Association, which looks for the best method for pouring concrete onto wood floors 鈥� construction done in mid-rise buildings for the purposes of sound attenuation and radiant heating.

Kelly said that due to the limitations of CLT 鈥� financial and otherwise 鈥� wood-framed projects between 20 and 40 stories would always be consigned to 鈥渄emonstration鈥� status, where they exist solely to prove a concept.

鈥淓veryone’s asking, 鈥楥an you do it?’ 鈥� he said. 鈥淲ell, yeah, you can do it. But would you do it?鈥�