A Denver developer hopes to put Colorado on the map by building new apartments with cutting-edge construction material: wood.
Wood has been used for thousands of years for houses and other buildings. However, the kind of wood Katz Development will use for its 12-story apartment project in Denver is made for what’s called mass-timber buildings, which are more common in Europe but are catching on in the U.S.
Ceilings, walls, floors, beams and columns in mass-timber construction are built with panels of wood layers, which are laminated and are perpendicular to each other, rather than steel and concrete. Using mass timber speeds up construction and takes fewer workers because the pieces are modular units that fit together like Lincoln Logs.
But a major reason Katz Development, a family-owned business, and other companies are turning to mass timber is because they believe it is more environmentally sustainable. Buildings and construction account for about 40% of the global greenhouse-gas emissions, according to the International Energy Agency.
The cement sector consumes about 7% of the world’s industrial energy use and produces 7% of the world’s carbon-dioxide emissions, according to IEA data.
“Mass timber is innovative and is happening in other parts of the world and it has been for a while. The U.S. has been a little slow to adopt it,” said Andrew Katz, who founded the company with his father, Scott. “We want to be on the forefront of whatever is new in the industry and mass timber is exactly that.”
Scott Katz is founder and president of Midland Retail in Cincinnati. Adam Katz, Andrew’s brother, is assistant project manager for Katz Development.
The company’s 12-story, mass-timber apartment building, planned at 3495 Wynkoop St. in the River North Art District, was one of six winners announced in June in the 2022 Mass Timber Competition: Building to Net-Zero Carbon. The project, called Return to Form, will get a $250,000 grant from the competition sponsored by the Softwood Lumber Board, an industry group, and the U.S. Forest Service.
When Return to Form is completed, it will likely be the tallest mass-timber structure in Colorado and possibly the second-tallest in the country. A 25-story mixed-use residential building in Milwaukee is the tallest and the next tallest is currently a 10-story building in Washington, D.C., said industry group WoodWorks.
“We hope to break ground in the spring of next year. We’re about halfway through the design period,” Katz said.
He expects construction to take 16 to 18 months. The 140,000-square-foot building, built on a 12,500-square-foot lot, will have 84 apartments and some ground-floor retail space. The first three stories, which include two levels of parking will be concrete, and nine above will be made of mass timber.
Katz is working with Tres Birds, a Denver architecture and design firm, and KL&A Engineers and Builders in Golden. The two firms were among the partners that shared the award in the mass-timber competition.
Greg Kingsley, president and CEO of KL&A, said the firm has worked on several projects involving timber. The projects include the Aspen Art Museum, the Strings music pavilion in Steamboat Springs and Platte Fifteen, a five-story office and retail building at Platte and 15th streets in Denver.
“We’ve been around 27 years and the very first project we did had some heavy timber components in it,” Kingsley said. “We’ve been working on timber buildings of some kind or another for our whole existence.”
Much of the timber comes from small trees, 6 to 9 inches in diameter, that were grown on private land. The kinds of wood commonly used are spruce, pine and Douglas fir. Kingsley said people ask about using the beetle-kill trees that pose hazards in the forest.
“The quick answer to that is we could have if we’d gotten on the stick while the beetles were still gnawing on it,” Kingsley said.
A dead, dried-out tree is too hard to work with, he added.
Kingsley called the flat wood panels fashioned from timber a game-changer.
“It’s cross-laminated timber. It’s sort of like plywood on steroids,” Kingsley said. “You lay down a series of boards in one direction and the boards on top go in the other direction, back and forth.”
The boards are glued together and put in a press to make a solid wood panel.
“All the work happens in the shop. The guys at the site just throw it together. It comes in pre-assembled pieces,” Kingsley said.
As a result, the construction takes fewer workers, is quicker and more quiet. And it’s better for the environment, Kingsley said.
Advocates of mass-timber buildings say they have much smaller carbon footprints than those with more steel and concrete. “It’s the only truly renewable construction material. You use it, you can grow it back, build with it and you can grow another (tree),” Kingsley said.
An important caveat is how the areas where the trees come from are managed. Kingsley said the mass timber used by his firm and others come from forests that are certified by third-party organizations as being sustainably managed. The wood isn’t coming from old-growth or rain forests, he said.
Timber supply chain
“The drive behind mass timber is largely to do with the climate impact of the materials that we typically build with, which are concrete and/or steel,” said Chris Magwood with RMI, a Colorado-based research and consulting organization focused on environmental sustainability.
Whether mass timber is more eco-friendly is complicated, Magwood added. “There are a lot of competing claims and metrics that people throw around that you can use to either make it look great or make it look terrible.”
Magwood, the manager in RMI’s carbon-free buildings program, said his organization hasn’t taken a position on mass-timber construction. “The upfront emissions of making a large timber building are much smaller,” he said.
A key, Magwood said, is whether the timber comes from well-managed, healthy forests. Forests can be carbon “sinks” if they absorb more carbon dioxide than they emit. Decaying or dead trees release carbon and carbon dioxide can escape from the soil.
Magwood said while there are several good certification programs that assess forest health and management, they don’t directly measure the carbon emitted by forestry practices. Some are working to include that in their standards.
“If we can do it well, it’s a great thing to be doing,” Magwood said. “We have to know that it’s never going to be the strategy for replacing all of our carbon-intensive buildings. There just aren’t enough forest stocks in the world.”
Katz hopes the companies involved with the Return to Form project help put Colorado on the forefront of mass-timber construction. He, Kingsley and others worked with Denver building officials to adopt new standards that will be part of the international building codes and will allow taller timber buildings. Denver is well ahead of other U.S. cities, Katz said.
The standards center on fire protection. The taller the building, the more of the wood has to be covered, with drywall or other material. However, extensive tests and research have shown that mass timber will hold up on par with other materials, Katz said.
Like burning a log in a fire, char forms on the outside of the wood, creating a protective layer, Kingsley said. People can calculate how thick a char layer needs to be to give people enough time to get out of the building.
Katz Development will use some of its $250,000 grant to analyze how much using timber reduces the building’s carbon impact. The contest winners will share what they do to encourage more mass-timber projects.
The buildings are beautiful and inviting, Katz said. People can see how the building is put together and can relate to the material because it’s familiar, he said.
“We really hope that lots of people follow this path and we hope that five or 10 years from now, we’re not the only high-rise timber building in Denver,” Katz said.