County of San Mateo Office Building 3 Wins Two ENR Awards

Truebeck is thrilled to announce the County of San Mateo Office Building 3 (COB3) has won two awards from ENR California’s 2024 Regional Best Projects: Best Government/Public Building and Excellence in Sustainability. Award recipients were selected by an independent group of AEC experts. Click here to see all the Best Projects winners, and here for the list of sustainability winners.

Configured into an H-shape, the 208,000sf, five-story building in Redwood City incorporates two generous public plazas, flexible office space, a gym, café, multi-purpose rooms, and board chambers for the San Mateo County Board of Supervisors. The interior features extensive areas of exposed wood, while the facade compliments with high-performing copper anodized aluminum panels alongside sizable glass segments, allowing natural light to flood the building. Truebeck additionally built a 368,000sf, seven-story parking structure with 1,200 stalls and 124 EV chargers.

The County of San Mateo COB3 project elevates the sustainability standard for civic projects. It is the first net-zero-energy civic building constructed with mass timber in the U.S. While a typical mass timber structure has 65–75% less embodied carbon than a conventional steel structure, COB3’s structural timber lowered its structural embodied carbon by 85%, setting a new benchmark in civic construction.

Solar arrays on site produce the energy needed for the building’s operations. Passive design strategies simultaneously reduce the building’s energy use. The glass enclosures on the building’s north and south facades are recessed and shaded, while on the east and west sides, a series of fins protect the windows. These measures minimize heat gain, reduce the need for artificial cooling, and optimize daylighting. Rather than diverting stormwater runoff to municipal treatment facilities, onsite bioretention planters will absorb and treat 100 percent of the site’s runoff. These solutions reduce environmental impact throughout the building’s life.

The project is also targeting LEED Platinum certification. To achieve this, Truebeck needed to achieve Sustainable Forestry Initiative (SFI) certification. With the County’s budget, the team, along with the wood manufacturer, needed to think creatively. The solution was to use Douglas Fir, an expensive but beautiful wood on the top and bottom that would be exposed, and use a more cost-effective wood for the middle three layers.

The project is an all-electric building with a high-performance envelope, mixed-mode ventilation, and onsite renewable energy. The building’s MEP systems are designed to be high-efficiency with enhanced redundancy, resiliency, and future flexibility. An interior zone VAV system takes advantage of increased economizer hours, reducing energy while providing higher outdoor air ventilation rates and improved indoor air quality. 190 automated operable windows along the perimeter provide natural ventilation each night when outdoor conditions are mild for passive cooling; sill-mounted fan coil units provide cooling and heating when needed. High-efficiency air-source heat pump/chillers provide cooling and heating to the air-handling units, fan coil units, and main lobby radiant floor. The lighting power densities and plug loads were reduced beyond Title 24 levels by 20%, targeting two of the largest energy end-uses. Onsite generation from a 333kW, 614,000 kWh photovoltaic array offsets the annual energy use of the building.

Reducing cost often reduces carbon, as fewer materials mean a decrease in embodied carbon. By using mass timber, the team was able to save on costly and carbon-filled materials, such as ceilings, by exposing the timber at every turn for a beautiful, nature-filled work environment without added expense. Carbon-reducing decisions were considered in every decision, from materials to construction activities.

Truebeck extends congratulations to our client, project team, and partners—thank you for all of your hard work that made these awards possible.