For decades, Portland International Airport has earned a reputation as one of the United States’ most passenger-friendly airports. With the completion of its main terminal expansion, it now has an architectural identity to match.
Designed by ZGF for the Port of Portland, the decade-long redevelopment has transformed the airport’s ageing terminal into a contemporary gateway that draws heavily on the landscapes, materials, and character of the Pacific Northwest. Rather than starting from scratch, the team chose to renovate and expand the existing terminal while keeping it fully operational, an ambitious undertaking that has culminated in the largest public infrastructure project ever delivered in Oregon.
The first thing visitors notice is the roof.
Spanning nine acres, the sweeping mass timber structure stretches across the terminal like a forest canopy. Rather than making steel its defining material, the terminal highlights locally sourced timber harvested from forests and mills within a 300-mile radius. The material choice reflects Oregon’s long association with the timber industry, but it also gives the building a warmth that is not often seen in airport architecture.
The design is less about making a statement and more about creating a feeling. ZGF wanted the journey through the terminal to echo the experience of walking beneath tall trees. Daylight filters through 49 skylights set within the timber lattice, casting shifting patterns across the interior much like sunlight passing through a woodland canopy. The basketweave pattern of the timber roof also draws inspiration from traditional Indigenous weaving techniques of the Pacific Northwest, adding another layer of regional identity to the design. Large windows frame views of the airfield beyond, while mature trees, cascading planting, and thousands of smaller plants soften the scale of the expansive public spaces.
The connection to nature extends well beyond aesthetics. Studies have long linked natural light and greenery to reduced stress, something airports rarely manage to provide. Here, planting also serves practical purposes, helping passengers navigate through the terminal while breaking down the vast interior into more intimate spaces.
Although the roof is the project’s defining feature, its construction tells an equally compelling story. Weighing approximately 18 million pounds, it was prefabricated into 18 large modules before being assembled above an airport that continued operating throughout the five-year construction programme. Delivering a project of this scale without disrupting day-to-day operations demanded careful planning and showed how prefabrication can simplify complex infrastructure projects.
The timber roof is only one part of a broader strategy to modernise the airport without losing the qualities that made Portland International Airport distinctive. Instead of replacing the terminal, ZGF carefully reworked and expanded the existing building, a decision that significantly reduced the project’s carbon footprint while avoiding years of disruption that a complete rebuild would have caused.
Inside, the airport has been designed to feel less like a transport hub and draws inspiration from Portland itself. Rather than creating one vast, uninterrupted terminal, ZGF organised the interior as a series of smaller spaces inspired by the city’s short blocks, walkable neighbourhoods, and public parks. Public areas before security include local restaurants, local retailers, generous seating, and gathering spaces that remain accessible whether passengers are travelling or simply meeting friends and family. Throughout the building, locally inspired materials, public art, and landscaping reinforce a strong sense of place rather than creating the anonymous atmosphere common to many large airports.
The project also looks well beyond today’s travel demands. Passenger capacity has effectively doubled, allowing the airport to accommodate around 35 million travellers annually by 2045. Behind the scenes, an all-electric ground-source heat pump system cuts energy use per square foot by half, while the extensive use of timber and the decision to renovate rather than rebuild contributed to an estimated 70% reduction in the project’s carbon footprint.
Less visible, but equally important, is the engineering built into the structure. Situated within the Cascadia Subduction Zone, Portland faces one of North America’s most significant seismic risks. The terminal has therefore been designed to withstand a magnitude 9.0 earthquake through a combination of seismic isolation bearings and flexible structural systems that allow controlled movement during a major event.
The completion of the second and final phase also introduces a redesigned arrivals experience. New exit routes improve passenger flow from the concourses to baggage claim, while expanded post-security areas provide additional seating, skylit all-user restrooms, local food and retail outlets, and new public art installations. Together, these additions complete a redevelopment that has unfolded in carefully planned stages over the past several years.
Recognition has followed throughout the project’s delivery. Since the opening of its first phase in 2024, the terminal has received accolades including the Prix Versailles World’s Most Beautiful Airport award and honours from the Holcim Foundation for Sustainable Construction, reflecting both its architectural ambition and environmental performance.
What ultimately distinguishes Portland International Airport is not simply the scale of its timber roof or its sustainability credentials. Many airports are becoming larger and more efficient. Far fewer attempt to create an experience that is unmistakably rooted in their own region. By drawing on Oregon’s forests, craftsmanship, and landscape, the terminal avoids the anonymous feel common to many large airports, giving travellers a distinctly Oregon welcome.
Through its design, ZGF has demonstrated how transport infrastructure can express local identity just as convincingly as any museum, civic building, or cultural institution.
Images: Courtesy of ZGF
