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Cross-laminated timber is continuing to gain popularity in Portland, and one of the most visible hot spots is the intersection of North Williams Avenue and Fremont Street.

There, the eight-story Carbon 12 was completed in 2017. A stone’s throw away, the five-story Radiator building was finished in 2014. Now, work is under way on The Canyons 鈥� a six-story mixed-use building 鈥� next to Carbon 12. All three mass-timber projects were developed by Kaiser Group and designed by Path Architecture.

For The Canyons, R&H Construction is serving as the general contractor.

鈥淓verybody’s excited about this project and what we’re doing,鈥� R&H Construction Senior Project Manager Adam Petersen said.

Crews broke ground on The Canyons in February 2019 and expect to finish sometime this summer. The 65-foot-tall, 110,000-square-foot building will hold 70 residential units. Crafted with seniors in mind, the building will offer physically accessible amenities and light-filled apartments with open floor plans. As a bonus, a resident paramedic will be available 24 hours a day.

At present, teams of craft workers representing a host of trades are spread out across the site. All of them are working underneath a temporary weather barrier covering the entire building. The structure was topped out several months ago, when the final 5-ply and 7-ply CLT panels were flown in for installation.

鈥淩ight now the roof is going on as weather allows, the weather barrier is being applied and the first windows are on site and are starting to be installed,鈥� Petersen said. 鈥淢EP teams are also roughing in units as fast as we can go, and we are a couple of weeks away from starting (insulation and drywall installation).鈥�

As senior project manager, Petersen fields many of the inquiries about the use of CLT for The Canyons. The project will be featured at the 2020 International Mass Timber Conference in Portland in March.

鈥淧eople are excited about it and we get asked about it, it seems like on every project,鈥� Petersen said. 鈥淓veryone wants to know: 鈥業s my project a good candidate for CLT?’ It can be tough trying to tell people that while it is a solution, and in some cases it is the best solution, it may not be the best solution for every project. It’s about trying to figure out the appropriate times and places to use it.鈥�

For The Canyons, crews are building two post-tensioned concrete decks and four stories of stick-framed walls. But instead of common Trus Joist I Joists (TJIs) fabricated by Weyerhaeuser, the team is using CLT panels for floors and ceilings. Much of the wood and many of the mechanical systems are being left exposed.

鈥淭his is sort of a hybrid that not a lot of people have thought of,鈥� Petersen said. 鈥淲ith steel and concrete buildings, everybody’s done it. But with CLT buildings, people are still being really creative about 鈥楥an we do it this way?’ and 鈥榃hat ways can we use to support this really great assembly?’鈥�

The evolution of CLT in the building industry is ongoing, and the many variables involved are still being examined by project teams.

鈥淵ou have to look at the whole development cost, I think,鈥� Petersen said. 鈥淏reaking down materials, TJIs are less expensive than CLT. But when you start to factor in the (drywall) ceilings and some of the other things you’re putting in, the equation changes.鈥�

Acoustics continue to be an issue, especially in multifamily projects, he added. The harder surface requires thicker acoustic matting and gypsum concrete assemblies, increasing the cost slightly.

鈥淭he science of it isn’t impossible to figure out,鈥� he said. 鈥淒epending on the layout and configuration, it’s maybe cost neutral. Maybe it’s a value saver, but maybe it makes sense to do it in some other way.鈥�

Then project teams must consider the fact that the few manufacturers of CLT panels all make products of different sizes. Clearly, there are still kinks to work out.

鈥淚t’s not simple,鈥� Petersen said.