In California wine country, north of San Francisco, Faulkner Architects repurposed a 1950s tack barn as part of a Glen Ellen retreat for a family of four. In addition to salvaging original construction materials and retaining the shape and atmosphere of the agricultural building, the architects minimized the accessory dwelling’s energy footprint with the optimization of cross ventilation as well as with the installation of a new radiant concrete slab for heating, which is complemented with a 10,000 BTU propane-fired boiler. Inspired by Glen Ellen’s strong agricultural roots and beautiful rural views, the clients sought a weekend retreat from the city that would pay homage to the landscape’s history.