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PDX Airport Main Terminal Expansion / photo: Nicholas Kielbasa

Oct 8, 2024 WoodWorks

By Kate Carrigg, PE, Regional Director, OR, ID-So, HI, WoodWorks 

In August, the Port of Portland celebrated the completion of the PDX Airport Main Terminal Expansion Project with ZGF Architects, KPFF Consulting Engineers, and General Contractor, Hoffman Skanska Joint Venture.  The new main terminal includes a massive, seismically isolated timber roof structure featuring veneer-based cross laminated timber (CLT) panels bending in double-curvature, 34,000 pieces of Douglas Fir lattice work, and over six miles of glulam beams (placed end-to-end), according to Rose Boleen.  Rose is currently working as a Project Manager with Timberlab, the mass timber fabricator and installer out of Portland, OR, that coordinated and performed the timber installation—an effort that took a team of 20 people 9,500 hours of detailing time to achieve.

I met Rose on a tour of the airport project while it was still under construction late last year.  Like many others who interviewed her, I was immediately drawn in by her knowledge of the airport project and her passion for timber construction.  When I learned more about her background, though, I realized how valuable her story was for young folks coming into our industry, in demonstrating the importance of genuine curiosity and a willingness to accept opportunities as they come along: 

Rose, you started your mass timber journey working on the First Tech Federal Credit Union project in Hillsboro, Oregon.  Walk me through your experience on the project, what was your most important lesson? 

Yes, I was an intern for Swinerton at the age of 21, and for two weeks I got to go to the First Tech Credit Union project.  There wasn’t much for me to do for those two weeks, so I felt most productive being out in the field.  I wanted to help the team so I was, you know, picking up wrapping off the ground and just being helpful wherever I could, and it was the greatest experience.

Organizing panels on the First Tech Federal Credit Union project in Hillsboro, Oregon / photo: Rose Bolleen 

At one point I had a stopwatch, and I was tracking crane pick times.  I was getting our production rate because we had nothing to go off; this was our first time (working with mass timber).   We had to hit a certain cycle time per CLT panel—I think it was a 2- to 3-minute cycle time per panel.  If we didn’t—if the crane ever stopped, if your workers are stopped—I was like “we’re losing money” and that was ingrained in my brain.  You have to make sure everyone is continually moving.  It’s quick.  It has to be quick, and I think that’s the coolest thing about mass timber! I will still go for runs past the building, and I get flooded with emotion from that first experience.  I just look back and I think, “I got lucky.”

You’ve come a long way from working as an intern on your first mass timber project to now working as a Project Manager on the Portland International Airport Terminal Expansion project. Tell me about that journey.

After the internship, I finished my degree in Construction Management, moved to Portland, and worked with Swinnerton on a year-long tenant improvement job downtown.  I remember Chris Evans came to me and said, “Hey, I’m going to start a rough carpentry install team, and I’m looking for a project engineer.  Do you want to come join the team?”  I had never even framed a wall, and he just handed me a book about the basics of rough carpentry and said, “Just read this book…”

My first job with that group was Ledding Library in Milwaukie (OR) and we self-performed the wall install.  We actually prefabricated the (panelized, light-frame) walls in a warehouse in North Portland that is now the Timberlab facility as you know it. I missed quite a few critical hold downs in that building. The poor engineer had to come out and walk the entire job with me and we had to do an RFI to fix all the hold downs I missed. I will never forget a hold down again. 

After that we started picking up a little bit more mass timber work, including the Hillsboro Hidden Creek Community Center and the Beaverton Public Safety Center.  I went out to the Lincoln City Police Station for the next eight months, and that was our first time doing CLT shear walls.  We also had intense slopes on the roof and a lot of steel integrating with the timber. This made the sequencing very important, and although there were some challenges, it turned out to be a beautiful project and a great learning experience.  Another cool thing about this project is that the walls are bulletproof, which influenced the decision to use CLT—because you can get the panels so thick.  I think they used 9-ply panels for the walls, and we had one 9-ply panel on the roof too.  It was our heaviest panel and the furthest away from the crane, so we had a huge crane on that job just for that one pick!

CLT shear walls on the Lincoln City Police Station / photo: Rose Bolleen 

After Lincoln City, I worked on the pre-construction side of the Kresge College Renewal project, which was a job for the University of California at Santa Cruz.  That’s where I was when Chris approached me again and said “Hey, we have the airport project.  Are you interested in joining the team?” …and I said “Absolutely.” 

How do you view those projects looking back compared to now, and how do they compare to the PDX Airport Expansion? 

You know, they seem like small projects compared to the airport, but they were also my first time doing it.  I think the overwhelming feeling you get when doing something new is what makes it challenging.  So yes, the airport is very complex, but having a couple years of experience from those small projects under my belt allowed me to feel much more confident on such a large-scale project. I take everything I work on to heart, and I genuinely care about every project.  In my heart they all hold the same amount of space. 

While we are on the topic of carrying over lessons learned, I noticed that the PDX Airport and the Kresge ACAD building at UC Santa Cruz both have curved roofs.  Can you share more about what techniques were used for each project?  Were you able to carry any lessons over from the ACAD roof? 

Oh yes, the ACAD building at UC Santa Cruz has a unique curvature to the roof, but it wasn’t as intense of a curve (it had a larger radius), so we could use solid sawn CLT panels, which are very stiff.  Because the curvatures were so intense between glulam beam profiles for the PDX Airport, we had to use a thinner, veneer-based panel with more flexibility.  We used 2 1/8” thick Mass Plywood Panels from Freres.    

For the PDX Airport, we did mockups.  In fact, we did three different mock-ups just make sure that it would work… because we failed, you know, three times… and the last thing you want to do is fail when you actually start the building—especially with a prefabricated product.  Look at it (plan it out) but then also do a small-scale mockup. 

It’s funny that you say that.  WoodWorks recently had a team building meeting where we competed to see who could build the tallest spaghetti tower, and then we watched a video about the challenge.  It turns out the people that have historically done the best in this competition, after structural engineers, is elementary school kids, because they don’t approach it with a preconceived idea of how to make it work—they approach it by prototyping!  They rapidly test a bunch of ideas until something works and then they run with it. 

Yes! That’s the best opportunity. Test it out. The Architect, ZGF, had a lot of smaller scale mock-ups of the roof too, and then to make sure the 2 1/8” thick panels would work, we did the full-scale mock-ups.  We built them in an old hangar at the airport that wasn’t being used anymore. 

Was the roof geometry the most challenging part of the PDX Airport project?  If not, what was the biggest challenge and how were you able to find success? 

The biggest challenge was just getting us organized.  I know that is a very simple way to answer it, but it was the complexity of organizing so many different parts and assigning deadlines to when things had to happen for us to stay on schedule.  I think that the beginning phase was extremely complex, and it happened during wildfires and COVID and material escalation.  So, we threw in these three unknowns that we had just not planned for.  The pre-planning was extremely complicated and difficult. When we started installing, I felt like I could take a step back and just enjoy the process. 

I think that is the most important part of a mass timber project: the pre-planning.  It relies so much on speed of construction… 

Yes, and if your kit of parts is not prepared properly then you can’t install. The largest loss of dollars on a job is your productivity.  Your manpower.  Nobody wants to lose productivity because of planning you didn’t do; it’s our people doing the install, and I want them to be successful.  

The second part of your question: why was it successful, and why did it work?  There’s something about a team that trusts each other, who all have the same end goal. We had to be open to ideas, otherwise it wasn’t going to work.  I remember when we first went down to Zip-O-Laminators in Eugene, the project manager at the time, Jared Revay, was on the floor with a floor plan of their facility.  He said something like, “If we lay out the manufacturing line like this, we can make it work.” 

It was so cool to see him take full ownership of what needed to happen. That’s what inspired my realization that we all have to work together to solve this problem.  Everyone in this room matters. So, that’s how I take this whole job—that it might be a once in a lifetime experience, but I’m always going to cherish that team I was a part of. 

I agree, an integrated and collaborative team is really what makes the difference, especially on a mass timber project.  The manufacturer and the trades have to be so much more involved, and everyone must be willing to coordinate if they want to take full advantage of prefabrication. 

Having gained all this experience with the PDX Airport and with your other projects, if you were going to give advice to someone else about starting a mass timber project what advice would you give? 

I want to tell people that you don’t need to get it right away, but be curious on your own, and then ask questions, and ask them until you understand it.  I had to ask the simplest questions.  I didn’t know what camber was, and these beams at the airport are all full of camber.  I also didn’t understand how the roof sections for the airport broke apart and moved for probably a full year, and for a full year I would always ask my superintendent the same question: I still don’t understand this, can you just explain it again to me? 

So I would encourage anyone getting started with mass timber that it’s okay to not get it at first, and to look at it as a great opportunity to really be able to learn it, understand it, and then teach someone else.  Once you teach someone, then you know that you’ve got it down. 

That’s an excellent piece of advice.  I’ve noticed that there really are a lot of folks in our industry, and especially young professionals, that feel like they’re expected to already know all the answers. Many times, they don’t feel comfortable asking questions.   

Yes, and I want to help people break down that barrier in their head.  It’s okay to not know.  Just be curious. 

So Rose, with the first phase of the PDX Airport Terminal project complete (congratulations!)— what’s next for you? 

Well, phase two will likely start at the end of this year, but the project I’ve been working on the last few months is the Multnomah East County Library in Gresham.  It’s 95,000 sf and has the largest mass timber columns that Timberlab has ever done. They’re almost 2ft by 4ft in width and depth, so you can barely wrap your arms around them!  It has almost 1,200 beams and 142 columns, and the tallest columns are about 27 or 28 feet tall, two stories in height.  Those are all exterior columns that will welcome you to the library. It’s going to be a gorgeous community space. My dad has his master’s in library science, which is not really a degree that you can get anymore, but I grew up going to libraries and they hold a very special place in my heart. I get to combine my passion with what he made his career out of and that’s a pretty cool opportunity.

A massive column for Multnomah East County Library – nearly 2’ x 4’ in width and depth / photo: Timberlab. 


Rose left me with a list of interesting facts about the PDX Main Terminal Project, which is open to the public as of August 14, 2024.  If you’re located close to Portland and you haven’t had an opportunity to see the airport yet, most of the new space is located before security.  That means locals can enjoy the timber-framed roof and forest-like atmosphere (with or without travel plans) while eating at local restaurants that have opened new locations at PDX. 

PDX Airport Facts

  • Glulam, veneer-based CLT and lattice account for 289,986 CF of lumber, or 3.4mil BF of Douglas Fir
  • 1.2 million individual fasteners 
  • Largest screw is 5/8” x 6’  
  • 9,500 hours of detailing time with a team of 20  
  • 1200+ unique lattice pieces – about 34,000 pieces  
  • Over 3.5 miles of glulam beams – manufactured in Oregon by Zip-o Laminators  
  • 272 x long span 80’ = 21,760ft = 4.12 miles for Total Long Span Beams- 6.22 miles total for all Glulam Beams 
  • Over 63 miles of lattice.  Enough to lay down end to end from PDX to Timberline lodge on mount hood – processed by Timberlab  
  • Approx. 500,000 LF of lattice = approx. 94 miles of lattice harvested, milled and fabricated for TCORE 
  • Approximately 10,400 trees were harvested for the glulam beams.  
  • The timber was sustainably sourced from Oregon and Washington – with significant contributions from Tribal-owned forests, including the Coquille Indian Tribe’s forestland in Southwest Oregon and Yakama Nation’s forestland in Central Washington.  
  • The Yakama Nation provided 370,000 board feet, the largest fiber contribution of any of the landowners involved. 
  • T-Core is the first project to use 5-axis cut operations at Timberlab  

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