Building with Mass Timber, with Pat Layton

Notable Quotes

• Mass timber stores carbon for a long time: “What we do with mass timber is we harvest those trees and convert them into a product—lumber or any other product. If we store those products, or if we use those products, the wood itself is stored (or sunk) for a long time, like in a building. Then, we have a carbon sink.” (7:57)
• How wood holds up in a fire compared to concrete and steel: “Wood is combustible. It will burn if exposed to high enough temperatures. But wood is fire resistant. Concrete or steel are not as fire resistant. If there is a hot fire in concrete or steel, you may lose strength, because the metal of steel or the metal in the rebar and concrete buildings—if it gets hot, it reduces the strength, and you may find failures there. Wood, as it gets hot, burns at a very predictable rate. We overengineer the size of a beam or a floor so that if it has heat, there is plenty of time for people to exit the building. Wood has strength, so it’s not going to fall down.” (16:06)
• Mass timber reduces total building costs: “Sometimes people get upset or worry about the cost of a piece of wood—but because wood is almost finished, the actual total building costs go down, even though a square meter of wood may be more expensive than a square meter of concrete. But the concrete needs a lot more stuff on it to finish it, whereas the wood can be finished pretty much as is, in fact.” (21:11)

Top of the Stack

• Woodworks Map of Mass Timber Projects
• Mass Timber Business Case Studies
• Cost Comparisons of Building with Mass Timber vs Other Materials
• Andy Quattlebaum Outdoor Education Center, a Building Created with Mass Timber
• Building Projects That Use Wood and Mass Timber as the Main Material

The Full Transcript

Kristin Hayes: Hello, and welcome to Resources Radio, a weekly podcast from Resources for the Future. I'm your host, Kristin Hayes. Today, I'm talking with Pat Layton from Clemson University, where she is Professor Emerita of Forestry and director of the Wood Utilization + Design Institute.

Pat and I are going to discuss a resurgence in constructing buildings with wood, and in particular, using a product called “mass timber.” It's a pretty fascinating tale of taking a historical practice, addressing some of its inherent and perceived issues, and updating it to meet twenty-first century needs. Pat not only knows mass timber from a research perspective, but also from an industry perspective, and has helped facilitate the construction of a mass-timber building—if not more than one—on Clemson's campus. I'm really looking forward to hearing about that, too. Stay with us.

Hi Pat, and welcome to Resources Radio. It is wonderful to talk with you today.

Pat Layton: Great. It's wonderful to be here, and I'm so glad to be able to talk about my favorite subject—mass timber.

Kristin Hayes: Fantastic. Before we talk about mass timber, let me give you a chance to introduce yourself to our listeners. I'd love to know more about how you came to work on forestry issues overall and mass timber, in particular.

Pat Layton: Sure. I was raised by a family who loved to fish and hunt, so I grew up outdoors, tomboy-style, back in the ‘50s and ‘60s and loved doing all of those things. When I went to college, I went into forestry when there were very few women there. I had a great professor who turned me on to a thing called “forest genetics,” which is tree breeding. I went through that route and got my master's and eventually, my PhD. I worked in industry, worked in biomass energy, and worked for a company called Scott Paper Company. I dearly loved that experience.

That took me all over the world doing forestry. Finally through a trade association in Washington, DC, where I learned more about a lot of things including wood and policy. Then I came to Clemson as a department chair in 1999. I worked here as a university administrator in the department of forestry and its various convolutions thereafter for 14 years.

The opportunity during those last four years of administration was to create something called the Wood Utilization + Design Institute. As people will remember, we had suffered through a housing-mortgage crisis prior to 2010, and mills were shutting down, and private forest landowners had no place to sell their wood—and especially, their logs for sawmills.

So, our state asked us, a land-grant university, "Help us solve this problem. We need new markets." And we started looking around for the opportunity to bring a product that was new to the United States and Canada—to North America—called mass timber into the United States, and maybe to South Carolina. [This] was [an opportunity] we couldn't turn down.

We decided to work with our colleagues in architecture, civil engineering, and other areas—construction science, for example—of our university, putting them all together and coming up with an institute to look at how we can increase the use of wood products. So, we created the Wood Institute. In 2014, I left my administrative position in the university and moved over to begin working at the institute. It's been the best 10 years of my life to do what I'm doing now.

Kristin Hayes: That is excellent. First of all, it's great to hear that you're enjoying this phase of your career, and you were highly recommended as the perfect person to talk to me about mass timber.

You mentioned markets and the desire for new wood products. I think that's where mass timber really comes in. Let me ask you to kick us off. Can you define mass timber for us? It's certainly different from the older style of wood-framed buildings that people might have in mind from centuries ago. What is mass timber, and what comprises it exactly?

Pat Layton: You're right, it does have its roots in what we call "heavy timber"—those big chunky pieces of wood that were cut out of large logs that we used to have 100, 200, or 500 years ago. But we don't cut those kinds of trees anymore.

Let me just explain what mass timber is—they are engineered wood products in which you can form boards laid on top of each other, and we glue them together. And those are referred to as glulam beams or glulam columns. We also take boards that are joined together and make a big flat panel out of them in which we'll use three to nine layers of those boards. Every time we change a layer, we cross it so that we have long, short, long, short, long, short. And that gives the board an extreme strength in both directions. It's a big panel product.

We call that “cross-laminated timber.” We can do the same thing with veneer products. We can make mass plywood panels. We can do all kinds of things now that we didn't know were possible 20 years or so ago. We're developing new technologies every day to utilize more of this wood, because we can use this engineered wood product. We have more strength and wider types of materials that we can put in these buildings with smaller sizes of wood.

We used to have to cut really big trees to get these big heavy timbers out of them. Now, we can cut normal-sized trees that we usually use in the sawmill industry and create these large, strong beams, columns, and panels that we can build these large buildings with; or even small buildings. I have a mass-timber panel on the roof of my pool house that we're just constructing—it's five plies thick, just went through a hurricane, and made it through safely. These are really chunky pieces of wood that are very strong and can take a lot of abuse and come through it.

Kristin Hayes: It sounds like that layering process is really critical to leading to that strength that you talked about, right? Sort of these layers upon layers.

Pat Layton: Yeah.

Kristin Hayes: Another piece of the puzzle that I wanted to ask you about is that Resources for the Future (RFF) is largely focused on climate solutions. I wanted to talk to you about the interplay between mass timber and carbon. How is mass timber considered a carbon sink? That's something that I've heard about, too, so I wanted to ask you about that interplay.

Pat Layton: Yes. Trees absorb carbon from the atmosphere, and in the presence of sunlight and water, photosynthesis happens, and that makes all of the cells and all of the trees that exist in the world. It is the way of sequestering carbon out of the atmosphere and storing it in wood. Trees don't live forever. If they fall over and die, their carbon is released back into the atmosphere as they rot.

What we do with mass timber is we harvest those trees and convert them into a product—lumber or any other product. If we store those products, or if we use those products, the wood itself is stored or sinked for a long time, like in a building. Then, we have a carbon sink. You are growing trees for … I'll say, in the Southeast, we might harvest mature trees that are pines when they are 25 to 35 years old.

In the Pacific Northwest, we may be talking 40 to 60 years old. In the Northeast, it's somewhere in the middle of those, or maybe a little bit longer. The farther north you go, it takes longer to grow the trees. What we do is we suck carbon out of the atmosphere, turn it into wood, and then convert wood into a product that's going to be in existence for a very long time.

As you may or may not know, wood buildings exist that are anywhere from … There are some that are 1,000 years old and some that are 150 years old. What we do find … There's been some studies that show that wooden buildings tend to last a really long time and that a lot of the concrete blocks or other types of buildings that have been built in some places aren't built to last. They're single use, whereas a lot of our older buildings have been renovated and reused, and so they're still around.

On my campus, we have heavy-timber buildings. The trees were grown in the 1700s and 1800s, and we built those buildings in the late 1800s. One of them that I tour around a lot was constructed in 1898. We've been using that building ever since for a variety of purposes. It's one of our historic buildings on campus, and we love it very much. But that carbon dioxide was set aside 130 years ago plus, and now it's been sitting in a building as a carbon sink ever since.

Kristin Hayes: I really do want to make sure I leave some time for you to talk about how building on campus is going, because I'm very intrigued by that.

Before we talk about the United States, I want to give a broader geographic perspective on building with mass timber, too. Where is building with mass timber most common? Did it start here in the United States? Is it something that has been taking off in various parts of the world, and how has that trajectory changed over time?

Pat Layton: Great question. With some of the products we use, like glulam beams, they've been around for 100-plus years, and the technology was developed either here or in Europe. There's been a lot of people involved in developing these technologies. While the concept of cross-laminated timber is recent—it really got going in the 1990s in Europe—some ideas about it have been around longer than that.

Laminated veneer lumber has been around since the 1960s—late ‘50s, early ‘60s—but it really got going … The cross-laminated timber got going in Europe and moved over to the United States and to Canada in the 2000s. So, it's a fairly new technology for all of us, and we didn't even have architects who knew how to use it.

As the forest-products industry gets into these products, we've actually had to go out and work with architects to help them understand how you might use this wood, how you might design a building, and what the benefits are. There's a lot of work that we've done and others have done to do that, and then to train our young architects today and the classes to use that—and they love it. The students are really into it. They've heard about it, and they want to use it. It really is pushing how we're teaching architecture today. There's been a lot involved.

We've also had to upgrade the building codes, because in the early 1900s—maybe even earlier in some places—building codes went away from wood, because people had seen places where fire had caused very bad things to happen. A lot of states banned building schools and large buildings with wood.

We've had to come back and do a lot of research to show how wood burns, how these mass-timber elements would burn. Building codes have increased to have sprinklers in them for most buildings these days so that we can control those areas. So, it's been a joint process of research, engagement, teaching, and opportunities to bring this back.

But we do see that people really enjoy being and locating their offices or living in some of these old buildings in our cities. Like in the Southeast, we have a lot of old textile mills, and those have been converted to businesses, condos, and all kinds of things. People love that loft style of building—those big buildings. So, there was a perceived need that this would go very well in commercial development. It was a time and place, and the right research and things got done, so that we could build that trajectory.

When I got started in this—when we got started in it in about 2011 or 2012, when we got a first grant to do some work on this—I could count the number of buildings in the United States on one hand. The first one was actually a house at Hilton Head, South Carolina, that was owned by a European, and he brought cross-laminated timber in to be the flooring in his new beach house. Then, around 2016, we saw a real uptick in the number of buildings that were beginning to start—and not just residences, but multiple buildings.

So, we began tracking it, and right now we have over 4,000 commercial buildings that are either already completed or are in design. They're coming along quite nicely. They started mostly in the Pacific Northwest, but they've proliferated throughout the United States. In fact, the tallest building made of mass timber in the United States is in Milwaukee. The next-highest building, which will be higher than the original highest building, is starting construction right now in Milwaukee. So, it’s interesting how it's grown and developed.

Kristin Hayes: Yeah. Milwaukee, the pioneer in this space. That's fantastic.

I want to lean into something that you just mentioned. Because for me, as a newbie on this topic, when I think of building with wood, I definitely think about fire. Really what made me want to talk to someone about this issue is that I was just in old Europe, where so many cities have been destroyed by these large-scale, massive fires.

I think that's actually one of the reasons why many societies moved away from building with wood, because it is too easy to burn. I did want to make sure to talk to you about mass timber and fire resistance, because my understanding is that we've really made tremendous progress on that fire-resistance issue. I wanted to ask you to lean in a little bit more and talk about what makes mass timber different in terms of its fire resistance.

Pat Layton: Sure. Let's do fire resistance really quickly. One, there are two terms that people need to understand. One is combustibility. Wood is combustible. It will burn if exposed to high enough temperatures. But wood is fire resistant. Concrete or steel are not as fire resistant. If there is a hot fire in concrete or steel, you may lose strength, because the metal of steel or the metal in the rebar and concrete buildings—if it gets hot, it reduces the strength, and you may find failures there.

Wood, as it gets hot, burns at a very predictable rate. We overengineer the size of a beam or a floor so that if it has heat, there is plenty of time for people to exit the building. Wood has strength, so it's not going to fall down or those things. That's just the big size, the big chunkiness of wood, and we understand a lot more about that.

One of the other things is that building codes have changed. We now have sprinkler systems in most buildings, and you're never going to get these, hopefully, large-scale, city-destroying fires ever again. That's one of the issues. And all buildings have those; that's important. Building codes are one of the most critical parts of this. As we move into wood, both in terms of fire resistance and strength, we've done all the testing we need to prove to those who manage the building codes that this works, or we would not have put it in. This is really important.

Kristin Hayes: Great. Thank you for that. I think that's a really important piece for our listeners to have a sense of what we're talking about in terms of that. Thank you for introducing us to those terms.

I want to talk more about other benefits. You mentioned how much this has really been appealing to architects, to designers, and to the people who are experiencing these buildings. Talk to me a little bit more, if you would, about the benefits that developers and designers are seeing, when they talk about building with mass timber.

Pat Layton: Yes, that's a great question. A couple of big things that are important in that area is that, one, wood is stronger than most of those other products, but it doesn't weigh a lot. Some of the first buildings that were built with mass timber were on really poor-quality soils, where you would have to go down very deep to put really deep pillars in the ground or to really load up a building. You had to go very deep or really dig out a lot of bad dirt and replace it. Having that lightweight frame, you could go higher in a city. For example, there's a building in San Francisco that's on some shaky soil, and it's settling and people are going to have to move out of it because that is a very heavy building. That's the kind of thing we think about.

The other thing is we usually do a lot of the manufacturing of these big segments of wood … They come to your site, and they are lifted by a crane and they go into place like Legos. It's very easy to put them together on-site. While there's a longer up front time to design a building, to get it engineered, and to get everything correct, once you get to the actual process of building, it goes quite quickly, because it comes in on a truck, gets lifted off by a crane and just pops together very fast. That's one of the big benefits.

The other is that you don't require as much labor to construct the building. A lot of these buildings go together with a crew of about 10 people and a crane operator. Any more, you've got too many people on the site. That's the difference. Because you're doing it so fast and so much of it's already been put together, you can get a building dried in quickly.

One of my friends used to tell me that once they got a floor finished, and they got the floors of the next floor up, which is the ceiling above the first floor, that their other contractors—like heating, ventilation, air-conditioning, and electrical—could chase them up the building. As they went up the building, you could be building below safely because you had a complete floor above you. In a lot of other building cases, you have to build those steel structures or put up the concrete structure, then pour the floors, then do this. You had to do it kind of in phases and it took longer.

Kristin Hayes: Right. Much more sequential.

Pat Layton: For example, an elevator shaft with mass timber takes you about a day and a half, and an elevator shaft out of concrete blocks or other types of materials can take 30 days. There's a lot of different things. Also, if you want to expose wood in the building, then you're not bringing in contractors who are going to do sheet rocking, ceiling tiles, and things like that.

While sometimes people get upset or worry about the cost of a piece of wood, because wood is almost finished, the actual total building costs goes down, even though a square meter of wood may be more expensive than a square meter of concrete. But the concrete needs a lot more stuff on it to finish it, whereas the wood can be finished pretty much as is, in fact. Because people like to see their wood, they like to touch it, feel it, smell it, and things like that. So, it's a fairly finished product.

Kristin Hayes: Interesting. And I'm really glad you mentioned cost, because it sounds like a lot of different factors come together to help determine the ultimate cost of building with mass timber. It's not just about the materials, it really is about all these other factors that come into play.

I'd love to hear a little bit more about the cost comparison, if you would, across the life-cycle of these buildings, and if you have a sense of how that has evolved or is looking to evolve in comparison with maybe more traditional materials. I'd love to hear more about that, too.

Pat Layton: Well, certainly we do see that wood cost can be very variable. During COVID, for example, the price of a two-by-four was a little high, because so many people were building with it in their homes. The housing industry is really one of the biggest uses of lumber. We're using that same lumber. In fact, we're using an offset of that lumber—a small, select part of that lumber. Only half of that kind of wood is actually going to go into mass timber.

Because of the quality, because we have to have good strong wood without a lot of knots and things like that, we're picky about our wood. But when you look at it, if the price of wood goes up and down like that, the price of concrete and steel doesn't usually move as much. You can count on it a little bit more and estimate better. But we're getting better at estimating.

Some of the companies that make this product, they're really good at figuring out what they think it's going to be. They're really good at estimating the cost. So, it is really understanding all of the cost involved and learning how to deal with it and finding a company who's going to do your construction and understands how to buy, how to bid, and how to secure that.

I'll tell you, one of the biggest deals is the contingency rate. They'll do this contingency fee. “Just in case something bad happens, we want to have this amount of money set aside.” We've seen that they'll throw high contingency fees on a building of this type, because they don't know how to build with it, and they don't know what to expect. So, when you go with someone who's already built with it, they drop their contingency fees, because they feel very safe and secure in what they're doing. They know this is going to work just the way I'm planning. For example, we were building our pool house, and one contractor said it would cost $18,000 to build, and I found a contractor locally who knew how to build with mass timber, and it took basically three and a half hours to unload the truck and get it on my building. It was only $3,000 to get it done; most was the cost of the crane.

It really is an understanding of what it takes and how you do it. When you've done it more than once, you really get in line. Some of these costs are dropping quite dramatically, but wood cost is a part of the portion that you have to worry about. When wood costs go up and down, it can deal with it. So, if you're not in a hurry, and you can wait a little bit, wood cost may come down, and you can get it cheaper.

We'll just see how this goes, but it is one of those things. There are times when concrete goes up, because the demand in other parts of the world or steel is hard to find, because we don't manufacture a lot of steel here in the United States, it has to come from international sources. We import a lot of the steel that gets used in buildings.

This recent strike on the ports could have affected buildings, because they couldn't get steel. There's many things in the building industry that you've got to take account of. So, everything has its own limitations. But in general, time, labor, and those kinds of things go down when you're using wood. There are excellent cost studies, examples of cost-comparison studies out there if somebody wants to read about those.

Kristin Hayes: Fantastic. Maybe we can link to one of those in our additional resources section of the podcast, too. That's great.

This is great, and as I said at the outset, I really want to make sure I leave at least one more question for you to talk about some of the work that you've been doing on campus at Clemson. I'm not sure if it's just one mass-timber building that you've spearheaded there or if it's actually multiple, but I'd love to hear a little bit more about those projects—how they came to life and if you have any more lessons beyond the ones that you've already shared with us from your experiences of building with mass timber that you'd want our listeners to know.

Pat Layton: We're now starting our fourth building. The first one was in 2019, and it went very fast. I would say we broke ground in January and had our occupancy permit in December. In fact, we would've been sooner, but there were some non-wood-related issues that delayed finishing the building. We should have been done in October. But it's a gorgeous building. It's an outdoor-recreation area for our students, so they can go in and check out camping goods, kayaks, or whatever. They love the building.

It is a hybrid, so it has steel columns, then glulam beams and cross-laminated timber floor plates and roof structure. It's a wonderful building and everybody loves it. Our president fell in love with it. I think, when we first started talking about if we could build a mass-timber building on our campus, our planner at the time was very modern in his outlook on how buildings should look. He said, "Well, you can go over on the other side of the lake." Because I think he thought it was going to look like a log cabin.

When we got done, he was like, "This is a very modern building. Very, very good." And our president, our coaches, our donors, our board absolutely love that building. Our next building was a chapel, and it's pretty traditional post and beam. In fact, it's with glulams; there is cross-laminated timber in it, but you can't see the cross-laminated timber, because they form part of the moment frame of the building, and they're hidden behind bricks. You can't really see them.

The third building is an alumni and development center with several other offices in it that we are just finishing. It will be open, hopefully, by April. There are two traditional buildings that are steel boxes, but in the center and between the two separate steel structures there is a glulam structure that marries those buildings through a very tall lobby and upstairs. Then, there's a mezzanine on the top of the building that crosses those two where it's, again, mass timber.

The beauty is there and is in gorgeous places on this building and really says some very unique things in a very service-oriented building. This is where COVID hit, and the price of the wood was through the roof. So, they backed off and went steel in a lot of the buildings where we had hoped it would be all wood. Lesson learned, you can adjust, but we still wanted the wood in it, because it's so gorgeous.

It's southern yellow pine, so it's the kind of tree we grow here in South Carolina. It makes a statement about the work that we've done as a university, being a land-grant university and working with these forests and the things we do there. And then, finally, our fourth building that we started now—we just have concrete out ready to start moving up—is the new forestry and environmental conservation building, where all of our forestry, wildlife, and environmental and natural resources students will be housed.

That one is going to be pretty much a post-and-beam building with glulam columns, beams, and then cross-laminated timber floors as we go up. It's also very modern looking. It's brick and metal on the exterior with a lot of glass. These all feed into our university sustainability policy and where we'd like to be going toward net zero as a whole university. They are also gorgeous. And we also have seen that, because of that, a lot of the architects that are working on projects that are going on in other parts of campus where they weren't thinking about mass timber, the interiors are turning into wood buildings. There is a large use of wood on the interiors of our buildings, because people like being around wood. They like the biophilia, as we say, in our world. That makes people have less stress; it's more commonplace.

We also have a program where, if we cut a tree down to build a building, we have to use that wood back in the building. So, we're reusing our wood or using our wood. If we cut it down to build, we're going to use it back in our building. And that's what we've done with the new forestry building. We'll be using a lot of wood on the interior of the building that is from projects that are being used around campus.

There was a stormwater project, and we got all their wood to use in our building, because we didn't have many trees on the site we were going to build on. It really helps warm up—if I can say that—the campus. So, even if you need a reason, like one of the buildings we have a lot of … We can't have vibration in it, so steel and concrete form a good non-vibration kind of floor system. We wanted to use the warmth of the wood in those buildings to just make people feel better about working in those locations.

Kristin Hayes: This sounds so wonderful. You're making me want to come, have a visit, and check out all these beautiful locations. I certainly know what you mean about biophilia and just that sense of being inside a wood building is really pleasant. Among the many other benefits that we've talked about, that's certainly one I can relate to.

Pat, I want to thank you so much for taking the time to talk through this with us, and I, of course, want to give you a chance to close with our regular feature, Top of The Stack. I'd invite any recommendations that you might want to recommend to our listeners about other good content—can be on this topic, can be more general—that you might want to recommend. What's on the top of your stack?

Pat Layton: There is a program called Woodworks, and they actually have a map on their woodworks.org platform, where you can go find out where all the mass-timber buildings are being built.

Kristin Hayes: Great. Road trip.

Pat Layton: Yes, absolutely.

Kristin Hayes: Pat, this has been really wonderful. Again, I really appreciate your introduction to all of these topics for us. I'm sure people are going to start noticing mass-timber buildings around them now. I feel like I certainly am.

Thank you again for your time and your insights.

Pat Layton: Wonderful. Take care.

Kristin Hayes: You’ve been listening to Resources Radio, a podcast from Resources for the Future (RFF). If you have a minute, we’d really appreciate you leaving us a rating or comment on your podcast platform of choice. Also, feel free to send us your suggestions for future episodes.

This podcast is made possible with the generous financial support of our listeners. You can help us continue producing these kinds of discussions on the topics that you care about by making a donation to Resources for the Future online at rff.org/donate.

RFF is an independent, nonprofit research institution in Washington, DC. Our mission is to improve our environmental, energy, and natural resource decisions through impartial economic research and policy engagement. The views expressed on this podcast are solely those of the podcast guests and may differ from those of RFF experts, its officers, or its directors. RFF does not take positions on specific legislative proposals.

Resources Radio is produced by Elizabeth Wason, with music by Daniel Raimi. Join us next week for another episode.