This undulating valley in Sonoma, California, was formed millions of years ago as magma from volcanic eruptions cooled—and more recently, it was affected by the devastating Nuns Fire. Granted the site’s history, durability and fire resistance were top of mind as a couple with two children reached out to Schwartz and Architecture to design a compact dwelling.

As he surveyed the landscape, founder and principal Neal J.S. Schwartz, noted how much volcanic rock had been exposed by the 2017 fire. “I remember picking one up and being shocked at how light they were, despite looking so dark and heavy,” he says. “We look to understand what makes each site unique—both in terms of geography, geology, and microclimates, and also visually and spatially.”

This approach led to an epiphany for the home’s design: Schwartz envisioned a simple yet sublime structure that peeks out of the valley like an ash-toned rock. “The roof took on a geometric, somewhat organic shape,” he says. “The way it sits on the base of the structure hints at the feeling of lightness in the volcanic and porous stone.”

Clad in sturdy metal and supported by a prefab wood truss, the roof is fire resistant by nature—and its beveled design makes it appear as if it’s floating atop the home. “In fact, the points of support are just pushed in a few feet from the solid face,” Schwartz explains.

Speaking about the clients’ brief, Schwartz says “it ultimately boiled down to a pool, a very small living space, and a workshop/garage—it’s a place for swimming, sleeping, and tinkering.”

The firm carefully sited the 816-square-foot home to preserve privacy—the side that faces the road is mostly closed off, while the opposite elevation opens wide to the valley below.

It’s also designed to work with the local climate. “The generous overhangs are calibrated with the sun to ensure that there are always areas of shade during the hot summer months, and the whole structure is oriented to capture cooling afternoon breezes as they flow up and down the valley,” says Schwartz.

The exterior of the home is clad in blackened cedar paneling that echoes the charred bark of the surrounding oak trees. “It is a technique used traditionally in Japan as a form of fire protection for homes,” explains Schwartz. Meanwhile, the interior’s airy ambiance offers a welcome counterpoint. “The owners selected a few simple materials that we then ensured were detailed cleanly. In particular, the contractor’s care with the plywood paneling really added warmth and handcraft to the interiors,” he says.

Although Schwartz and Architecture originally designed the home with a bay to section off one of its two bedrooms, in the end they decided to compress the plan. “Because the ‘core’ of the home was already in place, we could shrink and lengthen the floor plan without radically rethinking it,” Schwartz says.

This adds a lot of flexibility to the design—if the owners crave additional square footage in the future, Schwartz says that the basic truss and structural system is easily expandable. For now, the space is an apt retreat for solace and relaxation.

Related Reading:

To Rebuild After a Fire, a California Family Turns to Prefab

A Sonoma Prefab That Celebrates a Family’s Passion for Cooking

Steel-Clad Prefab Modules Perch Lightly in Northern California

Project Credits:

Architecture: Neal J.Z. Schwartz, FAIA (founder + principal), Christopher Wayne Baile (associate principal), Ania Burlinska (senior designer), S^A | Schwartz and Architecture / @schwartzandarchitecture

Structural Engineer: Framework Engineering

Civil Engineer: Bear Flag Engineering

Geotechnical Engineer: PJC & Associates

General Contractor: Eames Construction

Landscape Contractor: Totem Landscape Services

Lighting Designer: S^A | Schwartz and Architecture

Photography: Douglas Sterling / @douglassterlingphoto

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A Chunk of Volcanic Stone Inspires a Rock-Solid Sonoma Home