AIA San Francisco recently recognized the San Mateo County Office Building 3 (COB3) with an Honor Award at its 2025 Design Awards ceremony—the annual program celebrates the outstanding achievements in architecture and design of Bay Area individuals and organizations. Setting a new benchmark for sustainable public architecture, COB3 is the first net-zero energy civic building constructed with mass timber in the United States. The design for the 208,000-square-foot headquarters was driven by ambitious sustainability goals addressing both embodied and operational carbon, leveraging an innovative timber structural system that reduces materials and systems on site.
Climate leadership is needed now more than ever, and this county on the San Francisco Peninsula is particularly vulnerable to the perils of climate change including wildfire, drought, and sea-level rise. With a structural design that uses cross-laminated timber to reduce embodied carbon—by 85 percent relative to conventional steel construction—COB3 will stand as a testament to San Mateo County’s environmental stewardship. From an urban design perspective, the building’s H-shaped volume links two distinct and previously disconnected neighborhoods of Redwood City: the civic campus to the east and the downtown commercial core to the west. These create two new plazas linked by the glass-enclosed lobby that also acts as an event space and a pre-function area for the board chambers.
All occupants benefit from a design approach centered on biophilia and connections to nature, primarily the result of the exposed mass timber structure, along with images of nature and redwood trees reclaimed from the 2020 forest fires in San Mateo County. The all-electric project is scheduled to receive LEED Platinum certification with a design that lowered its embodied carbon by 75 percent compared to a standard building of its type.
