A San Francisco architect erects a self-sustaining building in a dense urban neighborhood.
Eco-minded architect David Baker lives, works, and constantly experiments at Shotwell Design Lab, a compound he owns in San Francisco’s Mission District. When he realized he could build a second residential unit in the rear of the property, Baker saw an opportunity to design a demonstration project that tested the latest innovations in sustainablity. The 712-square-foot Zero Cottage became the first net-zero, LEED Platinum, GreenPoint Rated, Passive House-certified residence in San Francisco after its completion in 2013. Passionate about hands-on exploration, Baker designed many of the building elements and furniture himself. Tiny details abound, illustrating the level of attention required for building net-zero in a city. “The beauty of Zero Cottage is that it doesn’t rely on a lot of advanced technology,” Baker says. “On a basic level, these things are within a lot of people’s reach today.”
The compact 712-square-foot cottage sits on top of a 430-square-foot workshop, where Baker’s firm prototypes and produces custom furnishings for his practice. “Not only is there room for more density on most residential blocks in San Francisco, but, if thoughtfully conceived, it also enriches our communities and makes our cities more resilient,” Baker says.
Metal shingles cut from scraps of sheet metal mix with new material as well as odds and ends, such as a road sign Baker bought at the Alameda Flea market. Baker designed stainless steel clips that allow any tile to be easily moved or replaced without the use of tools. Planter box panels add functionality to the facade and can be swapped out or relocated throughout the year.
Designed and prototyped by David Baker Architects, the building’s siding was made from salvaged maple flooring left over from another project. Inspired by the Japanese and Finnish practice of finishing exterior wood by charring, Baker used a roofing torch to char the boards and screwed them into vertical cedar battens.
Outfitted with shelves by EZ Shelving and a generic tool chest, the kitchen’s galvanized steel integrated counter and sink was designed by Baker and fabricated by DeFauw Design + Fabrication. A vintage pair of Norman Cherner’s Plycraft chairs and an A Chair by sustainable furniture-maker David Colwell surround a table by Pacassa Studios, which mounted a custom top on a Herman Miller Eames base. All appliances are electric, including heat-radiating panels, a combo washer-dryer unit, and an induction stove.
Accessed by a ladder with alternating treads, the sleeping loft features custom casework by Kevin P. Clarke Custom Woodwork that holds Kid Robot figurines, Hopi baskets, and an iPhone gramophone by Lawrence LaBianca. Lights by Pablo Designs are perched atop a bed that Baker designed. Peeking out from under the rug (made by Baker’s mother, Emilie) is a salvaged maple floor, which was finished with VOC-free flaxseed oil.
Rather than a one-off custom piece, Baker designed the daybed as a prototype and worked with Ohio Design on its fabrication.
The house's green roof is more of a brown roof: a desert-like array of native and non-native succulents that require minimal irrigation. The soil area is maintained with motorcycle tires (including one from a Harley hog), which control erosion. Composting takes place here as well.
As the roof had to be clear for fire department access, Baker developed a cantilevered frame for double-sided solar collectors that is elevated a few feet above the rooftop. The frame’s tilted configuration actually allows the panels to collect more energy than traditional flat designs. Seen here before the panels were installed, the frame holds sixteen photovoltaic collectors and is a 3KV system—large enough to generate more energy than the house requires in a single year.