The Sonoma weeHouse is a custom, high-end prefab residential project designed by Alchemy Architects for former Apple designer BJ Siegel and his wife. Completed in 2016, the house is located in the Santa Rosa valley, California, and is situated to maximize expansive views over the landscape. Design and architectural features Modular structure: The project is composed of two main prefabricated modules: a 640-square-foot main house and a 330-square-foot guesthouse. Minimalist aesthetic: The structures were designed as simple, open-sided boxes, echoing a minimalist aesthetic that the client favored. They sit on concrete plinths and are positioned to make the house feel as light on the ground as possible. Weathering steel facade: The exterior is clad in corrugated weathering steel (Corten), which has a distinctive rusting finish that helps the building blend into the natural, rural landscape of seasonal grasses and oak trees. Expansive glass walls: Both modules feature nine-foot-tall sliding glass walls, enabling the interiors to open up to the outdoors and connect inhabitants with the surrounding nature. Cantilevered deck: An outdoor porch cantilevers over the valley, extending the living space out into the landscape. This posed a unique construction challenge that required a separate module to be attached on-site. Ipe and oak interiors: The interior is lined with durable, textured ipe wood, which contrasts with the minimalist Cor-Ten exterior. The main living space features an oak "bedbox," and the cabinetry uses oiled oak. Interior layout: The main house functions like a studio, with an open-plan kitchen, living area, and a semi-enclosed sleeping space. Recessed pocket doors and screens, including a drop-down insect screen, minimize visual clutter. Construction and delivery The prefab modules were designed in Minnesota by Alchemy Architects and were fabricated in a factory in Oregon. The modules were delivered to the California site about 90% complete, significantly reducing on-site construction time and labor. Steel accessories, such as stairs and porch railings, were prefabricated separately in Minnesota and also delivered to the site. A crane was used to carefully place the structures on the concrete foundations between the existing oak trees. Credits Architects: Alchemy Architects (Lead Architect: Geoffrey Warner). Client and Design Collaborator: BJ Siegel. Completion Year: 2016. Builder: Fidelity Builders Inc.. Interior Design: Alchemy. Photographs: Geoffrey Warner. Awards: The design received the American Institute of Architecture's Small Project Award in 2018.