SEA-TAC C1 Expansion Proposal
Seattle, Washington

Seattle, Washington
Client: Seattle-Tacoma International Airport
Function: Civic
Total Floor Area: 226,530 sf
Building Floors: 6 floors
Status: Ongoing
The SEA-TAC C1 Building Expansion, a collaboration between Corgan and MZA, reimagines the airport experience through a synthesis of passenger comfort, sustainability, and a distinct Pacific Northwest identity. Rooted in intensive research, stakeholder engagement, and innovative design processes, the project enhances flow, visibility, and the integration of dining and retail while prioritizing daylight access and sustainable strategies. The expansion creates a seamless, welcoming environment that reflects the region’s spirit, elevating both the functional and emotional journeys of travelers.

“vision of an open, tree-like atrium that branches upward to form terraces of natural light, vegetation, and community space.” |

The interior atrium of the SEA-TAC C1 Expansion unfolds as a multi-level garden, where natural light, greenery, and warm timber accents create an uplifting passenger experience. Layered circulation paths and vibrant retail frontages seamlessly integrate moments of movement and pause, evoking the spirit of a lively, organic marketplace within the airport’s core.
Bathed in natural light, the central plaza of the SEA-TAC C1 Expansion becomes a vibrant urban living room, where lush vertical gardens and sculpted terraces create an inviting backdrop for dining, shopping, and gathering. The interplay of wood, glass, and greenery establishes a warm, biophilic environment that redefines the airport experience.


At the arrival threshold, a sweeping canopy of wood and glass leads travelers upward through a vibrant, daylight-filled atrium. Lush plantings, sculpted escalators, and cascading terraces guide movement organically, creating a seamless connection between the architecture and the natural spirit of the Pacific Northwest.
An expansive light-filled atrium unfolds through a composition of layered terraces, natural materials, and living greenery. Warm wood textures, polished metal columns, and cascading plants evoke a vibrant Pacific Northwest forest, offering travelers an uplifting and memorable spatial experience.


The sectional perspective reveals a dynamic interplay between indoor gathering spaces and an expansive outdoor plaza. Layered circulation paths, landscaped terraces, and sculptural elements seamlessly connect the terminal’s multiple levels, reinforcing a sense of openness, flow, and community.