by Zach Mortice
Associate Editor

How do you . . . design a highly sustainable set of community buildings that are strictly contextual and deferential to their surrounding landscape?

Summary: Portola Valley Town Center, by the architecture firms Siegel and Strain and Goring and Straja, uses reclaimed and recycled materials to complement and respect the natural landscape of surrounding redwood forests. While maintaining a rustic, organic air of informality with their cabin-like materials, the buildings’ emphasis on civic space marks them as dignified public structures.

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All images courtesy of Goring and Straja

1. Photovoltaic panels line the roof of the buildings.

2. Alder trees from the building site were used as columns.

3. Each of the building’s glass-lined, glowing entrances open to the town plaza.

4. Portola Valley Town Center.

5. Intersecting ceiling planes reflect the upturned roofs of the buildings.

6. Horizontal louvered sunscreens prevent excess solar heat gain.

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In a valley of redwood forests on the southwest outskirts of the California Bay area, the town of Portola Valley is a place of exceptional means and discriminating tastes. After the town hired the Emeryville, Calif.-based firms of Siegel and Strain and Goring and Straja to design their new town center in 2004, they raised about $17 million of the project’s total $20 million budget in about a year, and a city council member told firm principal Jim Goring, AIA, that “Woodside [a neighboring community] is about show and tell. Portola Valley is about hide and seek.”

Indeed, this cluster of 4,500 or so venture capitalists, doctors, and college professors didn’t want their new civic center complex to broadcast ostentaciousness. Keeping these new buildings in step with the surrounding landscape was valued more than anything else.

So the partnership between the two firms delivered a library, town hall, and community center (completed in November) that are simple gabled, wood structures with glowing entrance porches—welcoming lanterns that open to a public plaza. It all expresses the town’s organic, relaxed Northern California sensibility while still recognizing the fundamental dignity of municipal civic space and strictly conforming to the landscape’s context in a highly sustainable way.

Getting along with the land, and the town
Both Goring and Larry Strain, FAIA, of Siegel and Strain, praise their clients in the town as expertly informed and engaged, but their first clues as to the town’s aesthetic sensibility didn’t require hours and hours of meetings. Portola Valley’s design guidelines aren’t shy about telling the architecture to be shy. They advise architects to “avoid architectural features that increase visual prominence” and to “use colors and materials that blend in with the natural environment” so that everything can be “in keeping with the rural character of the town.” These guidelines make such a design job sound as if it were tailor-made for the California Modernist William Turnbull, perhaps most known for his Sea Ranch condominiums in Sonoma County, who would approach each building as a contextual extension and resolution of the natural landscape. Fortunately, both Goring and Strain worked for Turnbull for years.

The partnership of the two firms, who each took active design roles, was aided by the fact that the locations of their offices make them nearly next-door neighbors in Emeryville. Goring enlisted Strain and his firm after he realized the need for sustainable design expertise on the project.

“He didn’t stand a chance of getting the job on his own,” says Strain jocularly. Strain’s firm had the sustainability experience Goring needed, and Goring and Straja had completed many similar community-type buildings, often using wood, which was sure to be the project’s material solution.

“We all did a little bit of everything,” says Strain, who grew up in Portola Valley.

“Horse barn with a library”
Despite the community’s strict design guidelines, Goring says the town’s building stock contains no overriding style or aesthetic. “It’s not like going to a New England village where there’s a very strong and pronounced vernacular that you need to respond to directly.”

The three buildings (a library to the north, a town hall to the west, and a community center to the south) that both firms designed encompass 20,000 square feet on an 11-acre site. They all open and envelope a town square plaza and performance lawn on three sides, creating a strong locus for civic interaction. These single-story structures are low-slung and largely built from reclaimed and recycled building materials. Their forms and materials are rustic and informal, but the buildings’ site orientation and organization gives the plan appropriate civic prestige by placing an active center dedicated to peoples’ municipal and public lives in the center of the town. Again, Goring’s conception of the buildings walks a line between coarse and principled. “We directly wanted to try to give a sense of a horse barn with a library in it,” he says.

But it’s still a wholly contextual affair, barren of grand, constructed processions and formal ceremonial motifs. Even its most expressive features were designed in total deference to the landscape. Goring and Strain designed each building’s entrance with an upturned, slanting roof to preserve sightlines through expansive wood-framed windows out to the surrounding redwood forests, which might have been blocked with deeply gabled overhanging roofs. Goring also says these upturned roof sections mark the public’s entrance into each building’s civic sphere and optimize the position of the photovoltaic panels (which will generate at least a quarter of the building’s power) placed on each building’s roof.

Premium on sustainability
To prevent excess light and heat from entering the buildings through these wrap-around windows, horizontal louvers supported by thin steel columns wrap around the top of each building’s entrance areas. These louvers, made from Alaska yellow cedar, which will age to a light silver color, will reflect light in yet still screen light out in the summer, diffusing the glow of each building’s interior into a warm lantern presence on the town plaza. Approached from an angle, the wedge-shaped transparency of these windows gives the welcoming appearance of the opening flap of a teepee, another vernacular structure defined by the subsequent quasi-public space created through its grouping with others.

Elsewhere, the buildings’ redwood exterior siding was reclaimed and recycled from other buildings. Re-milled decking from the buildings previously on site is used for interior wood paneling. In another rustic touch, interior columns are made from alder trees felled on the site for the new construction. Though the bark remains on these tree trunks, steel columns were inserted in them. The interior ceiling of the buildings are made with fir/hemlock slats reclaimed from the roof decking of a school building that was on site. The slats are a counterpoint to the intersecting and slanting roof planes.

From the beginning, the project placed a premium on sustainability and the use of reclaimed and recycled materials, and Strain says 25 percent of the project’s wood was recycled. Half of this came directly from buildings that were already on site (a public elementary school, an administration building, and a multipurpose building). Strain says he didn’t feel limited by this narrower selection of materials at all. “I would have had a hard time building that much redwood building if they weren’t reclaimed,” he says. “You don’t see the same quality because it’s new growth.”

The concrete masonry and asphalt from the original site has been reused as base rock, building paths, and trails, and new concrete contains recycled fly ash and slag. A rainwater cistern and irrigation system will be installed soon. In the library, a public control panel monitors the buildings’ performance and shows visitors how much energy and carbon dioxide is being produced and consumed. Goring and Strain are aiming for LEED® Platinum certification.

But clearly, the Portola Valley Town Center isn’t a high-tech expression of sustainability. Its reliance on millennia-old passive design techniques is expressed in its materials, form, and quiet integration with the landscape.

“I would categorize the sustainable solution idea as being mostly applied common sense,” says Goring. “A lot of solar orientation issues were what people figured out 6,000 years ago and then forgot for the last 40 years.”