Near the peak of the dot-com bubble in 1998, a San Francisco couple built a second home in Sonoma for under $1 million. Nothing that unusual—just another attractive Wine Country house you wouldn’t mind being invited to for dinner. But when you consider that the house is constructed of earthen walls some 18 inches thick, with reclaimed cedar and hydronic heating, this was actually an anti-bubble house in which architect and client wanted to make a point about sustainability years before it became an industry buzzword.
“At that time people weren’t even using words like ‘sustainable,’” says architect Cass Calder Smith, AIA, whose firm, CCS Architecture, has offices in San Francisco and New York. In the vernacular of the time, the homeowners, Peter Boyer, an artist, and Terry Gamble, an author, told Smith that they wanted something “alternative.” Because they didn’t want a “wine estate” and forbade the use of Sheetrock, “I summed that up as ‘summer-camp sustainable,’” says Smith, who describes the style of the architecture as “aesthetic based on rural barns.”
Boyer and Gamble had an interest in green technologies and were considering such alternative methods as straw-bale and conventional rammed-earth construction. A colleague, the structural engineer Bruce King, convinced them to visit the Napa home of noted rammed-earth expert David Easton, which included a lab with examples of the walls. By that time, Easton had already built some 150 houses using the ancient technique and written his first book on the subject, The Rammed Earth House. King, in fact, had written the book’s structural engineering chapter.
The walls are constructed using PISE (pneumatically impacted stabilized earth)—a refinement of rammed-earth wall construction that is less labor-intensive. The acronym is also a play on pisé de terre, an 18th-century method of constructing walls with compacted dirt, lime, and chalk. “The walls are built with raw materials that are considered either unprocessed or waste aggregates that require less cement than concrete for strength and stability,” Easton explains. Instead of using soil from the site, which would require testing, Easton used a by-product of rock crushing, salvaged from a nearby quarry. The PISE method’s thick walls also need less energy for heating and cooling, and require no painting or other maintenance, says Easton.
“We absolutely fell in love with the material,” Boyer says. The earthen walls were used for the living areas, which constitute about two-thirds of the house. A covered breezeway connects the living areas to a wing with two bedrooms, made using traditional wood frame construction. The idea was to create a hybrid structure that would echo older farm buildings that had been put together piecemeal over time. “We didn’t want a Wine Country mansion,” Boyer adds, “but a very modest building.”
Other eco-worthy features included in the house: fly-ash concrete for the foundations, recycled structural steel, salvaged cedar, dual-glazed windows, a natural ventilation system, and solar thermal panels that create the hot water for the radiant heat.
How has the house held up? “Gorgeously,” Boyer says. Despite summertime temperatures that can hit triple digits, the house remains cool without air conditioning. For Smith, the project reaffirmed for him the right way to approach architecture: not through the lens of one sustainable attribute, but as a whole. “You need to site a house really well, let the light in, make it efficient, and use materials that are unique or sustainable,” he says. “Everything really plays a part.”