AIA/COTE awards Portola Valley project for Green credentials
The $20 million Portola Valley Town Center replaced three town structures—a library, community hall, and town hall—that sat on top of the San Andreas fault. Completed in 2008 the project is one of ten projects to be awarded the distinction of the AIA/COTE Top Ten Green Projects 2009.
The new project, set on a surplus public school site, replaced the buildings and turned the old site into a park and play fields. The library contains reading rooms, a children's area, staff offices, and a room devoted to town heritage. The town hall houses the administrative offices; building, planning, and engineering departments; and the town's emergency operations center. The community hall provides a large divisible multi-purpose room, two activity rooms, storage, and a catering kitchen.
The public was very involved in the design process, and a task force established goals that were used as a metric by the town council, citizenry, and the design team to evaluate design proposals including exemplifing the town's rural design ideals that compliment the landscape and taking advantage of the beautiful site while preserving open space.
The new town center achieves these goals by weaving together oak woodlands, playing fields, and new buildings into a civic center that meets the town's goals to compliment the natural beauty of the landscape in the greenest way possible.
The seismically unsafe, old town center was deconstructed; materials from the buildings were reused as beams, paneling, countertops, and structural fill. The new buildings are 20% smaller. The exterior siding and louvers are salvaged wood, and the wood flooring is local eucalyptus. The concrete mix is 70% slag. These and other measures reduced construction carbon emissions by 32%.
Proper building orientation, daylighting, natural ventilation, sunshades, and thermal mass reduced overall energy use and allowed for smaller mechanical systems. Small, efficient air-conditioning units pre-cool make-up air and eliminate the need for full air conditioning. The 76 kW photovoltaic system supplies 40% of the electricity used by the building; nonrenewable energy costs are reduced by 51% and operating carbon is reduced by 76.2 tons per year.
This project was chosen as an AIA Committee on the Environment Top Ten Green Project for 2009. It was submitted by Siegel & Strain in Emeryville, California and co-designed by Goring & Straja.