Behind The Curtain Walls: Seattle’s Tower Architecture


Image by My pictures are CC0 from Pixabay

Most downtown office towers in Seattle are unexciting boxes covered with curtain walls. Iconic structures like London’s 30 St. Mary Axe (2004, Norman Foster) haven’t come along in Seattle, even with our tech boom. For more than three decades, Seattle has been earnestly shaping policy and procedure to get better downtown buildings, and fend off the worst. What have we got to show for it? Rainier Square Tower. 

Columbia Tower, F5 Tower and Seattle Municipal Tower

Our original trauma was the rise of Martin Selig’s outsized Columbia Center (1985, Chester L. Lindsey). That project stirred outrage among Seattle’s civic-minded architects, who decried its dark reflective surfaces and its middle-finger-like 76-story height. (One critic, Fred Bassetti, tried to do better with the next-door Seattle Municipal Tower.) The Columbia Center furor led to the first-ever height limits in downtown Seattle, and eventually to design review and a refined zoning code with differing height limits. Over time, it probably inspired some of the visible structural elements in subsequent skyscrapers, like Bassetti’s Municipal Tower with its visible columns and bracing, and F5 Tower (2017, Zimmer Gunsul Fraska Architects), with its fractal diagonals.

Just as the city had planned, the just-ended boom has brought many mixed-use residential towers to Seattle, responding to Amazon’s hiring sprees. Amazon’s new wave of office towers was shaped by the company’s favorite architect, NBBJ, and the alliance between the two has shaped Seattle. 

It really began in 2012 when Amazon assembled land in the Denny Triangle to expand its urban corporate campus. The Spheres, with showy structural elements, are strong and beautiful, transparent, and partially open to the public. In the meantime, the real action began with five corporate office buildings, all rising quickly. But still, most of our new office towers have opaque sides, protecting a steel-and-concrete box from the weather. 

Curtain walls really never went away. But our new ones, built in the last decade, are better. For one, they’re not deathstar black like the Columbia Center monolith. Also, they’re not postmodern like some of the towers of the 1980s, shaped to look like classical temples in an imaginary city of the gods, like 1201 Third Avenue for example (1988, Kohn Pederson Fox). The curtain walls of the Amazon-NBBJ corporate buildings are detailed with an impressive array of glass and metal. Like most office tower walls, they help with energy efficiency—admitting light and reflecting heat. They look smarter, too, like they could be easily tuned to signals from other galaxies.   

The best new curtain walls are also honest and hard-working. They’re designed to be seen for what they are—screens and weather protection. As if to prove it, the edges of new curtain walls tend to rise above roofs, shielding assorted mechanical elements from view. Decorative, make-believe tops—like the postmodern towers of the late 1980s, are out. 

In the decade since the planning of the Amazon campus, the zoning envelope of Seattle has filled up—mostly with residential towers, a building type with its own issues. In the latest boom, new towers rose so fast in Seattle that our home-grown design review process got clogged and its volunteer panelists tired. 

Amazon and NBBJ, along with structural engineer Magnusson Klemencic Associates (MKA), have had an outsized influence on downtown Seattle, defining a generation of urban office towers. As it turns out, the tech giant won’t occupy Rainier Square Tower, but it was designed by the same team responsible for the company’s office towers (architect NBBJ and structural engineer MKA), at a time when it was assumed Amazon would be the main tenant.  

Rainier Square Tower topped out at 58 stories, the second highest building in Seattle. It’s unique bootlike shape might suggest an unusual structural system. There’s a hard-working steel and concrete frame in the center of the tall, thin part. The structure sets new standards for seismic safety, according to engineer John Hooper of MKA, and the heavy lifting is done around the concrete elevator column on the tall side. 

At Rainier Square Tower, the curtain wall accommodates the sweeping parabolic curve of the east wall, like a hammock held high at one side. It’s a feature that helps the new project stand up to the uncanny drama of the original 41-story Rainier Tower (Minoru Yamasaki, 1977) which is perched up on a solid, 11-story-high tapered pedestal. MKA’s predecessor firm did the engineering on that one, too. 

Generous floor-to-floor height provides room for a lot of cabling and cooling to serve those offices and the structural elevator column leaves a lot of undifferentiated floor area and space at the outer edge of each floor.  

In its basic design, however, Rainier Square Tower is yet another curtain wall office building with a covering of glass and metal. True, there is more drama and detail on its facades. Facets in the walls of Rainier Square Tower seem to mark the height of a story, making the floor levels readable from the outside. Streaks of opaque white add to the visual complexity.

To my mind, the best architecture gives us a better sense of what’s inside the walls, including the building structure. They may have missed this chance with Amazon’s towers, but the NBBJ-MKA team is together again on another downtown office building called The Net, to be built by UrbanVisions at 801 Third Avenue. This building will flash its structural system in all directions.  Renderings show transparent walls with a visible inner cage of bracing, lit for visual impact, though not easily seen. Lesson finally learned?

Clair Enlow
Clair Enlow
Clair Enlow is a freelance journalist writing about architecture, planning and history. She’s a Loeb Fellow and an honorary member of AIASeattle.


  1. Clair,
    Thank you for making the Seattle skyline more comprehensible, even, approachable to me. I have watched it change since 1949, and growing up we had our favorites: the Smith Tower, surely, but also the Northern Life Tower and many of the older masonry structures, with lovely interiors and resplendent with exterior tusked walruses and big-nosed Indian chiefs. I still recall my excitement when the Norton Building appeared in ’59, and my wonderment when I noticed it looked just like what I could build with my white plastic, green windowed skyscraper kit.

    I also remember thinking that Seattle seemed much larger before skyscrapers became common I think if was the massive appearance of masonry buildings, there rich interiors, and the fact that because they weren’t that high, they impressed all the more. But I was also struck by how small the office spaces in them were, particularly in the Smith Tower.

    And I cannot get over thinking that modern Seattle has been built with structures that are usually a decade out of style or because other cities have them. While a local style appears to have developed for private homes, the bigger buildings seem imported and standardized.. But I did love the jokes like Henry Moore’s massive bronze vertebrae picked clean in front of the Seafirst Building, dubbed the box the Space Needle came in. It is up their with Picasso’s ghastly vulture presented to Chicago, giving the city ‘the bird’ as it were. And the owners went along with these put-downs, apparently because no advertising is bad advertising.

    When we still met at Post Alley I appreciated my walks downtown to see the changes, quite bracing, but looking very fragile and tentative, built as though the structures are not expected to last. I wonder how they will fare when the Seattle fault decides to snap.

    I appreciate your precise writing and wonderful choice of words. You capture what I assume is intended by the building, but also what seems perilously obvious. I still wish someone would find a way to translate the work of Isadore and Anthemius to a modern setting, where Hagia Sophia’s vast interior spaces and light lift one up rather than oppress, so that, in the words of the Kievan Rus who attended liturgy there, “we no longer knew whether we were in heavan or on earth”. In a city so dark and gray, I would think a golden interior light open to all would have a place.

    Anyway, thank you for your fine article. David M. Buerge.


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