Mill Valley Residence

The canopy roof extends from the outside into the living space.


These Mill Valley homeowners decided to build a 640-square-foot guest house to complement their existing home on a small, level clearing at the top of a steeply sloping lot. They brought on Eric Haesloop, FAIA, of Turnbull Griffin Haesloop Architects to design a building that serves multiple generations and functions, including a guest room for visiting parents and friends, a media room, and a hangout space for teenage children. The homeowners felt strongly about designing the house with minimal, durable materials and making the space easy to care for.

Mill Valley Residence

The round skylight in the bathroom matches the exterior canopy.

The mature cedar and redwood trees surrounding the site played a crucial role in the design. The flat roof punctuated by round skylights extends the dappled light from the tree canopies over the expansive porch and indoor spaces. Wood siding lets the walls blend in with the trees, while the porch’s ceiling and skylight pattern become a playful facade seen from the house and backyard. The porch and media room are situated on the more open side of the site, and the guest room is tucked into the trees.

The porch, cool roof, closed cell insulation, LED lighting, and high-efficiency boiler keep the energy loads minimal, exceeding the California Title 24 Building Energy Efficiency Standards by 33 percent. Title 24 Standards were designed to ensure that new and existing buildings achieve energy efficiency and preserve outdoor and indoor environmental quality. This makes buildings more comfortable—with lower energy costs and reduced greenhouse gas emissions—and ensures that builders use the most energy-efficient construction. In addition, the guesthouse’s small footprint maximizes outdoor use.

The homeowners wasted no time utilizing the space for their family; shortly after completing the project, they hosted an 18th birthday party complete with music and disco lights.


AIA East Bay is an architectural community spanning the counties of Alameda, Contra Costa, Napa, and Solano. Our many programs include education for architects and outreach to the community on vital topics, such as sustainable design, earthquake safety, and architect-related issues that focus on how the Bay Area community benefits from well-informed design and development.