The 9th & Thomas building offers 12 stories of luxury office space with a sense of community after opening its doors to many local businesses and partners. The multi-use building, located in Seattle’s rapidly changing South Lake Union neighborhood, features a street-level space with retail, restaurant, and arts programming that serves as a neighborhood hub. One goal of this development was to design a building that would act as a dialogue about the connections between people and places, movement and urban form, and nature and the city. This goal was achieved through the integration of several green spaces and a primarily glazed façade that enhances the building’s transparency to the outdoors.

Our team joined the project during the design phase, assuming the role of building enclosure consultant. Olson Kundig led the design team and Sellen Construction was the construction manager. The project’s goals around connectivity and openness hinged heavily on whether the design team could utilize its desired unitized curtain wall system. As with any project that incorporates large areas of glazing, the team needed to take several measures to provide a comfortable environment for the building occupants and to meet energy code requirements.

By joining the project early in the design phase, our team was able to help develop the assembly selection criterion. We steered the project team to select a high-performance glazing system and unique wall assemblies that would enable the project to comply with the Washington State and Seattle energy codes. The design integrated various balconies, so our team needed to work closely with Olson Kundig to develop interface details that would prevent the enclosure system from being compromised.

During the construction phase, we worked alongside the contractor to ensure the construction conformed with the original design. We verified this with water leakage and whole-building air barrier testing. The 9th & Thomas project was completed in 2018, and because of the design decisions that were made, the building achieved LEED Gold Certification.


March 26, 2020


9th & Thomas Partners, LLC


Olson Kundig

General Contractor:

Sellen Construction

Our Role:

Building Enclosure Consultant

Key Services

Concept Review
Construction Document Review
Field Review

Before material and systems selections are finalized, our clients benefit from a review of the building enclosure design strategies at a conceptual level. This review provides an opportunity to reflect upon the performance expectations and fundamental building science strategies behind the selection of appropriate solutions. Experience shows that changes made at the conceptual stage of building enclosure design have far greater cost-to-benefit impact than those made during late design or construction. A typical concept review considers the following:

  • Environmental loads
  • Energy performance targets and compliance options
  • Life cycle expectations
  • Constructability, sequencing, and complexity of detailing
  • Structural support
  • Risk analysis

Michael Kramer | LEED AP

Principal, Senior Building Science Specialist
View Bio

David W. Fox | PE

Associate, Senior Project Manager
View Bio

Kinects Tower

Kinects Tower is a 41-story, mixed-use tower that is designed to accommodate the lifestyles of those who live and work in downtown Seattle.

Read More
Bullitt Center

Bullitt Center

The Bullitt Center is a flagship building designed to be the first commercial office structure to meet the International Living Futures Institute's Living Building Challenge: the building is self-sufficient for energy and water, it is pedestrian-, bike-, and transit-friendly, and it contains no "Red List" hazardous building materials.

Read More
RDH Building Science