Is Mass Timber the Future of America’s Skylines?

If there’s one defining trend in American architecture over the last decade, it’s the rediscovery of wood as a construction material. Mass timber buildings—made from large wooden panels, columns, and beams—are rising across North America, with developers racing to construct the tallest wooden tower. A new contender, the 32-story Edison in Milwaukee, just broke ground and is set to claim the title of the tallest mass timber building in the Western Hemisphere.

But why are American developers, architects, and builders all timberstruck? There are the carbon emissions—wood pulls down carbon dioxide from the atmosphere as trees grow, so these buildings are a tool in the fight against climate change. Plus, they are quick to construct and can be cheaper to build. So should we start building everything out of wood?

In Part 2 of the latest episode of Deep Green, produced in partnership with Mannington Commercial, METROPOLIS editor in chief Avinash Rajagopal speaks with DLR Group principal, Stephen Cavanaugh, who has been working with the developer Hines on the T3 series of wooden buildings all over North America. They discuss the thinking behind T3, what lessons Cavanaugh has learned over the five completed projects and the six more he has going underway, and how he thinks mass timber might change how America builds. Read an excerpt from his discussion with Rajagopal below or listen to the full episode on the Surround Podcast Network.

Avinash Rajagopal (AR): So, what are the T3 buildings and how did DLR Group get involved?

Stephen Cavanaugh (SC): To begin, T3 means Timber, Transit, and Technology. It was a decision by Hines, the developer of the projects, our client, to give this kind of unique office product a brand. They wanted to celebrate the idea that it was made of wood.

A lot of different things led to it, but one was this idea that you could build a workplace that was more environmentally and socially sustainable. Certainly, there were a lot of other factors that launched the first T3. Central business districts had lost some of their luster to redevelopment districts on the outskirts of towns. These areas had beautiful old brick and beam warehouse buildings that people were turning into residences and loft offices. But the buildings had drawbacks from a technical standpoint, daylighting, and systems efficiency of the envelope. Hines owned a lot of these buildings, and they were always a hundred percent full.

People loved these buildings, but Hines noticed that people would terminate their leases and leave because of discomfort. They thought, “Hey, there’s got to be a way to recreate the charm of these old loft buildings in a modern way that still delivers everything you’d expect from a Class A office tower.”

Apart from its universal design appeal, there was this alignment with the constraints of building of mass timber. The codes have been evolving to allow more, and still to this day, there’s this sort of 85-foot datum for exposed mass timber. That’s since evolved, but at the time, those code and zoning constraints actually aligned well with what Hines was envisioning.

They asked, “Well, if we can’t build that high anyway, can we explore wood?” The next step was figuring out how to break through the barriers to adopting this kind of construction.

AR: I think we all have a general sense that wood buildings are good because the trees sequester carbon as they grow. Then, if you make a building out of that wood, you don’t end up with the same carbon footprint you’d have using steel, concrete, or other materials.

What is it that helps maximize that potential of the environmental sustainability of these projects? What have you added to that very basic understanding that maybe we may all share by having worked on so many of these buildings? Where are the great advantages? What should we be doing so that we keep that advantage of the wood and the carbon footprint?

SC: The people that are building our wood office buildings are usually pretty sophisticated general contracting companies. They’ve built massive databases of cost and scheduling information for all the systems they regularly use, along with established relationships with subcontractors. [Introducing mass timber into that process] is like throwing a wrench into that system, right? Suddenly, we’re not going to make the superstructure out of steel or concrete—it’s wood. Where are we going to get it? Who’s going to erect it? That really has been the focus of our work, as you can imagine. With that trepidation comes a cost premium. How do we get around that? The whole idea is to build more with wood and only use concrete where we absolutely have to.

So how do we get around that premium? Because not all our clients want to do the right thing, and we study numerous ways to frame the building.

You want something that’s logical and divisible, something useful for a variety of users. With our Hines T3 projects, these are speculative office buildings, so they must work for a variety of users. We’re looking for something very flexible and then optimal in terms of the span, so that is a big part of the design.

AR: That is so fascinating. Doing the one big vanity, mass timber building as a one-off project is one thing, but what you’ve done is to repeat that, city after city, this kind of learning, right?

How important are the aesthetics of these buildings to their success economically? Also, how do you make sure that beauty is an integral part of your design approach? How do you celebrate that beauty of the wood in your buildings?

SC: Yeah, that’s the key word–celebrating. I’ve had to learn to adjust my approach to design, and I call it sort of getting out of the way—believing in the integrity of the building and the materials.

Certainly, there’s all the detail in terms of the specs and the meetings you have with the contractors to ensure that they’re treating the material with care that they might not use with other systems. Wood is beautiful and sustainable, and it spans very effectively but it’s terrible acoustically, because it’s such a lightweight material. We’ve developed an approach on these projects that’s really about getting out of the way and celebrating everything that you have. If we have to use concrete for lateral systems at the core, we expose it and polish it.

AR: We saw some of the early American mass timber experiments happen everywhere, but then very quickly, because the strength of American forestry is, we started to see a lot of high-profile projects in the Pacific Northwest and had never lost their tradition of wood buildings. I feel like I’ve gotten stuck with that association a little bit, but the incredible thing you’re doing with T3 is you’re putting these buildings up in cities all over the country, and yet in every city, you strive to make these buildings appropriate for the location they’re in.  How are you dealing with mass timber in this contextual way?

SC: Since the inception of this idea—Timber Transit Technology (T3)—we’ve been placing these buildings in transit-connected neighborhoods, so there’s always been an acute awareness of the surroundings. A lot of these sites are in these redevelopment districts on the fringe of cities, so there’s already that automatic connection with the turn-of-the-century brick-and-beam mercantile building with the new modern wood structure. We have that going for us.

On T3 Austin, for example, we did everything—we were the design architect, architect of record, and interior designer for the public spaces in the building. We were able to dive a little deeper into that idea, and our interior design team connected with local artists, artisans, millworkers.

We try to infuse some of that local charm. Early on, in the Minneapolis project, we were defaulting to a clean, modern aesthetic because we were referencing European projects.

But then we started to weave [more local charm] in that building. For example, a local muralist did some work, and we took some historical images from a former manufacturer that was on that site and printed those onto some of the wood panels and on the booths. We’re just trying to knit in some of the local history.

AR: That’s incredible! Stephen, if you had to pick one thing, a book, or maybe a building, or maybe an expert, somebody who’s been thinking about wood, that has either inspired you or you’ve really come to appreciate, and you think will inspire our listeners on Mass Timber. Can you pick something for us, a recommendation?

SC: On the technical and design side of things, just go to Woodworks. They publish a mass timber design manual. It’s got tons of great information and case studies. In terms of inspiration conceptually, I would direct you toward Michael Green’s TED Talk “Why We Should Build Wooden Skyscrapers”

I remember sharing that very video with the Hines team when we first started talking. He was inspirational for me. I was fortunate enough to collaborate with Michael Green after that.

AR: It’s wonderful. Stephen, thank you so much for spending this time with us today. And for talking to us about your incredible work on the T3 series of buildings, the scale and range of what you’ve accomplished through these buildings is truly remarkable. And I do hope it’s going to be one of the reasons that we change the way we build today.

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