COURTESY OF SIEGEL & STRAIN ARCHITECTS
The Portola Valley Town Center, an 11-acre project in Portola Valley, CA, including a town hall, a library, a community hall, and playing fields, is now complete. Emeryville, CA-based Siegel & Strain Architects, with Goring & Straja Architects of San Francisco, designed
the project. Designed to enhance energy
efficiency and reduce carbon emissions, the town center is expected to achieve a Platinum rating from the U.S. Green Building Council's Leadership in Energy and Environmental Design (LEED) program.
Tucked between a redwood grove, an old orchard, and a newly restored creek, the buildings are grouped around a town plaza and performance lawn that serves as the living room for the town's 4,500 residents. The town hall houses the city's administrative, planning, building, and public works departments. The community hall offers large public meeting rooms, as well as two activity rooms to accommodate classes.
"Our goal was to help the town preserve and enhance the site's natural characteristics," says Siegel & Strain Founder and Principal Larry Strain. "We designed the buildings to fit Portola Valley's rural character and to demonstrate the town's commitment to open space."
"This project has had an extraordinary amount of public support, scrutiny, and input throughout," adds Jim Goring, principal at Goring & Straja. "That has pushed and challenged the whole team to deliver a place that is both sustainable in the environment and compelling in the landscape."
The buildings are designed to use 33-percent less energy than mandated by building codes. A combination of thermal mass, natural ventilation, efficient compressors, and nighttime cooling
- which uses cool night air to lower the building's temperature in the evening - enables the buildings to remain comfortable during the day with minimal energy consumption. A building dashboard allows staff and visitors to monitor their energy and water use in real time. Large photovoltaic arrays on the roof of the library and community hall buildings supply a substantial amount of the town center's electric power.
The buildings incorporate a number of innovative materials and construction strategies as well. Reclaimed wood
from the old school buildings on-site was reused extensively. Existing concrete and paving were crushed on-site and reused for building pads and road base. All of the solid wood framing is certified as originating from well-managed forests, and the buildings are sided with reclaimed redwood from logs and timbers from northern California. The concrete mix replaces 50 percent of the Portland cement with blast furnace slag, reducing the carbon footprint of the concrete by 125 tons. Overall, carbon emissions from construction were reduced by 225 tons - 25-percent less than conventional construction would have produced.