There was a time when a new airport terminal evoked a sense of awe. When Minoru Yamasaki’s Lambert Terminal in St. Louis, with its vaulted, intersecting thin-shell-concrete domes opened in 1956, it amazed the construction world and set the stage for increasingly breathtaking jet age endeavors like Walther Prokosch’s circular cantilevered JFK Pan Am Terminal (1960), Eero Saarinen’s soaring, winglike TWA Flight Center (1962), also at JFK, and Saarinen’s upthrusting Dulles Airport in Washington, D.C. (1962). All employed concrete, glass, and steel in daring new ways that evoked the still-astonishing drama of airplane flight.
But in the U.S. at least, magic in airport design seems like a thing of the past. Even pricey, well-conceived recent terminals, like the new LaGuardia Airport in New York or the expansion of Tom Bradley International terminal at LAX, have struggled to capture popular imagination. But thanks to ZGF’s new terminal expansion of Portland International Airport (PDX), that run, I predict, is about to be over.
The $2.15 billion facility replaces what was previously a quilt of patched-together buildings. It is one of the most stunning American airport spaces in decades. But in this case, the exciting new technology isn’t really new at all. It’s wood, highlighted by an extraordinarily intricate 380,000-square-foot Douglas fir roof composed of over 800 curved glulam beams (some 80 to 90 feet long), 842,000 board feet of mass plywood roofing, and more than 36,900 pieces of 2-by-6 infill panels. This timber extravaganza, organized and fabricated via cutting-edge tools like CNC milling, BIM modeling, and both prefab and modular construction, is married to a supporting structure of steel y columns and girders. According to ZGF, it’s the largest mass timber roof in the U.S. and the largest mass timber structure of its kind in the world.
The wonder you feel when you first enter the space derives from so many sources. There is the epic scale, presenting a material we think we know in breathtaking new dimension—36 feet above you, everywhere you can see. There’s the hypnotic pattern of the timber pieces, whose long lines our eyes can’t help but follow and that literally lifts us from the mundane world of air travel. There are also concave sections that recall the hulls of boats. The sensation here is also about how good the material feels around us: It calms and warms us in what is usually the most uncalm and artificial of environments. We’ve been removed from robust natural materials in these kinds of settings for so long that this feels like a liberation. We’re looking into the future while going back to our roots. (Bad pun intended.)
Walking through the terminal is meant to approximate a walk in the forest, leading you through varied, evocative spaces and experiences. There are large, unfolding circle- and oval-shaped openings, topped by skylights, that evoke clearings. There are moments of compression and expansion; bustle and activity; quiet and loud. Bosques of trees (there are over 70 live trees throughout the project) in varied densities and compositions add to the sense of rustic calm, as do exposed timber pavilions for concessions and, in places, oak parquet flooring. Just prior to security, a double-winged wood conversation stair leads to a second-floor beer hall and an art gallery. All the while mammoth glass curtain walls, located at the ends of the terminal’s long axes, keep you oriented and connected to the outdoors.
While most airports seem like they could be anywhere, this one reflects Portland’s longtime role as the gateway to the country’s Northwest timber belt. It’s a “timber mecca,” as Sam Dicke, business development manager at Timberlab (one of the project’s Portland-based timber fabricators) put it. It also reflects local passion for the outdoors and the tradition of basket-weaving, passed from Indigenous communities to contemporary craftspeople. The space incorporated several local retailers into its concession areas, which are laid out, effectively, to approximate the width and dimensions of local streets and sidewalks. A slew of public art pieces reflect the city’s artsy side. And callouts to the previous terminal are here, too, like sections of the patterned green carpet (it approximates the plan of the airport itself), which for years has stood as the popular symbol of this place. Check out Instagram for endless foot selfies on top of it.
The choice of mass timber was, not surprisingly, also an environmental one. Wood is far less carbon-intensive than steel and concrete. ZGF designers noted that the timber roof represents a 125-percent reduction in embodied carbon compared with a traditional steel structure. (Another key to the reduction was the reuse of the lower levels of the original terminal for infrastructural support—ZGF says the project gained a 70-percent reduction in overall structural embodied carbon via reuse and material optimization.) All wood was sourced from within 300 miles of the airport, often from local landowners and native tribes, and it’s 100-percent traceable.
“It’s about getting away from the catalog model and creating new pathways and transparency,” said Nat Slayton, ZGF principal. The region’s evolving use of mass timber has largely replaced the gutting of old-growth trees. If responsibly managed, Dicke added, timber farming can aid in wildfire management, thanks to the relearning of old techniques like thinning, controlled burns, and replanting.
The airport is seeking LEED Gold certification—not an easy task for this type of building.
This is achieved by leveraging natural light (60 percent of the terminal is daylit); a tight envelope; targeted cooling; and an all-electric, ground-source heat pump system, which provides 95 percent of the terminal’s heating and 100 percent of the cooling. To prepare for the region’s predicted earthquakes (magnitude 9 is in play), the roof and curtain walls are set on seismic base isolation bearings that can move up to 24 inches in any direction. In the case of a major event, the airport, added Slayton, would become a hub for recovery and rebuilding.
The choice of wood was far more practical than conventional techniques. PDX needed to remain operational during construction, which had to proceed quickly and safely, so the terminal was erected over partially demolished structures and a portion of the tarmac. Timber, more than 10 times lighter than steel, was the best material to form into square modules or cassettes, measuring 100 feet-by-300 feet. These were then wheeled over from the fabrication site half a mile away and assembled on site. (More modules will be transported over for phase 2, which is scheduled for completion in early 2026.) Timberlab, which oversaw the roof’s timber sourcing, CNC cutting, and fabrication, tattooed QR codes onto each piece, all relating to a massive BIM model. “It was really a logistical marvel,” said Dicke. “It’s a 3D puzzle,” added ZGF architect Christian Schoewe.
The roof hovers over an open expanse, with no interrupting walls, and only 34 steel y columns. According to Schoewe, the old terminal had over 600. It’s an airy, luminous, and unified space whose informal changes are marked by shifts in the ceiling itself. The openness makes it flexible—a priority in a space that will inevitably change with shifts in load, security, and public demands.
Phase 2 of the terminal will include new entryways and more concessions, circulation space, and baggage areas. And there will inevitably be more work following, but according to Vince Granato, chief projects officer for the Port of Portland, the airport’s owner and operator, that scope has not been determined.
Already ZGF and the port are getting inquiries on the design from airports around the world. “We’re giving others the confidence that you can do it,” said Slayton. And it’s clear that the project is already a triumph for Portland itself. “It’s a reflection that this city can do big things,” said Granato. “It will be a real shining light for the region. There’s a lot of excitement here.…I think everybody has this immense feeling of pride in what we’ve been able to do here. We can’t wait to show it off.”
Sam Lubell is editor at large at Metropolis and has written more than ten books about architecture for Phaidon, Rizzoli, Monacelli Press, and Artbook D.A.P.
Project Specifications
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- Architect: ZGF
- Interior designer: ZGF
- Landscape architecture: PLACE Landscape Architecture
- General contractor: Hoffman Skanska Joint Venture
- Structural engineer: KPFF, Arup
- MEP Engineer: PAE Engineers, Arup
- Mass timber trade partner: Swinerton
- Steel: W&W | AFCO Steel
- Mass timber fabricators: Zip-O-Laminators, Timberlab, Freres, Calvert
- Mass timber manufacturers: Calvert, Freres, Zip-O-Laminators
- Wood adviser: Sustainable Northwest Wood
- Lumber mills: Elk Creek Forest Products, Frank Lumber, Freres, Herbert Lumber, Kasters Kustom Cutting, Manke Lumber, Zip-O-Log Mills
- Biophilic design consultant: Terrapin Bright Green
- Sustainability consultant: ZGF, Arup
- Glass: Carey Glass with Glas Trösch, Viracon
- Acoustical ceilings: Armstrong World Industries
- Wood flooring: Zena Forest Products
- Paints and stains: Timber Pro Coatings
