San Mateo County Office Building (COB3)

The San Mateo County Office Building 3 (COB3) is the first net-zero energy civic building constructed with mass timber in the U.S. Every decision in construction detailing and structural design was motivated by the goal of diminishing the building’s carbon footprint. The design leverages an innovative timber structural system to reduce materials and systems on site, reducing embodied carbon by 85% relative to conventional steel or concrete construction.

Acknowledging specific climate vulnerabilities, the design was driven by ambitious sustainability goals addressing both embodied and operational carbon. This all-electric project is on track to achieve Net Zero Energy and LEED Platinum certification.

Setting a new benchmark for sustainable civic architecture, the 208,000-square-foot headquarters offers County employees and residents a forward-looking headquarters that reflects the values of the community. From an urban design perspective, the H-shaped volume is configured to link two distinct and previously disconnected neighborhoods of Redwood City: the civic campus to the east, and the downtown commercial core to the west.

The workplace breaks down large floor plates into intimate sections to maximize natural light and ventilation. Operable windows provide natural cooling to reduce thermal loads, lessening the reliance on mechanical systems and improving occupant well-being. All occupants benefit from a design approach centered on biophilia, primarily the result of the use of Cross Laminated Timber exposed ceilings, glulam beams and columns, creating a sense of connection to nature. Echoing the timber structural frame, wood wraps the lobby interior and exposed wood elements continue throughout the 5-story building.