Mass Timber floor layout at Northlake Commons, a full-scale timber structure in Seattle, WA.

© Weber Thompson

© Weber Thompson

© Weber Thompson

© Weber Thompson

Lab-Ready Office in Mass Timber

Northlake Commons | Seattle, WA


This 275,000 square foot mixed-use project spans five stories, with 158,000 square feet of mass timber office and lab-ready space, over a concrete podium parking garage and warehouse for Dunn Lumber. The project will be located on the Northeast side of Lake Union, with access to the Cheshiahud Lake Union Loop. Weber Thompson's design of Northlake Commons "draws inspiration from the experience of being deep within the woods of the Pacific Northwest."

The high-performance lab-ready office building pays homage to the timber roots of the Dunn family business located on this street from 1931 to today. The structural system is comprised of CLT panels atop glulam columns and girders, with a steel Buckling-Restrained Braced Frame lateral system.

The mass timber structural system will have a lighter footprint than other structural alternatives; a Life Cycle Assessment of the embodied carbon in the timber will be calculated to understand the impact compared to more conventional construction types. The project is pursuing LEED CS Gold and Fitwel Certification.


Developer | Hess Callahan Grey Group

Architect | Weber Thompson

Structural Engineer | DCI Engineers

General Contractor | Swinerton


On the Northlake Commons project, the typical column-to-beam connections are achieved by routing a bearing pocket into the top of the column, creating a goalpost condition for the beam to bear inside. The beams simply bear on the ledge created by the pocket and are held in place by the column posts until fastening from above can occur. While this bearing pocket column has a longer CNC fabrication time than columns with steel connectors, the beams require only minor milling and thus have a much shorter CNC fabrication time. The majority of mass timber designs have more beams than columns, allowing for an overall reduction in fabrication duration. The CLT floor panels are then CNC fabricated in the factory by Timberlab supply partners to perfectly receive the goal-posted columns for a flush installation process.


The Northlake Commons development is a prominent display of mass timber and one of the first uses of the building material for lab-ready design. The project's structural system is comprised of glulam columns/girders and CLT, while the lateral system uses steel buckling-restrained braced frames. 158,000 SF of mass timber will be used for lab space specifically. Mass Timber was ultimately selected in this application for its weight-bearing and vibration performance.


Sitting at the northern edge of Lake Union, the building pays homage to the outdoors through 65,000 SF of intentional outdoor programming across the building's extensive ground-floor plazas and courtyard commons. The project team wanted to create a "walk through the forest concept" with a call back to where the timber was sourced on the building. Northlake Commons features multiple layers of forest-centered design, including a forest floor, understory, and forest canopy Connected by the city's bike network, Northlake Common's open-space plazas will provide a direct link to public amenities like Gas Works Park. Through human-centric design, the exposed mass timber structure and natural amenities elevate the workplace for a healthy and sustainable office experience.


The building's structural mass timber system was procured regionally, with glulam and cross-laminated timber supply coming from British Columbia. Timberlab provided custom fabrication services from its Portland, OR, facility and installed the entire mass timber package. The regional capacity to source and fabricate this project significantly lowered the overall carbon footprint of the structure. The total carbon benefit of the Northlake Commons project is approximately 4,000 metric tons of CO2, equating to roughly 1,000 cars off the road for an entire year.


Transformational Seattle Mass Timber Commercial Development Heralds New Era for Sustainable Design

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