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Mill Valley Hillside / McGlashan Architecture

  • Architects: McGlashan Architecture
  • Location: Mill Valley, CA, USA
  • Director In Charge: Scott McGlashan
  • Landscape Architect: Calandra Design
  • Structural Engineering: Santos & Urrutia Inc.
  • Project Year: 2009
  • Photographs: Courtesy of McGlashan Architecture

Courtesy of McGlashan Architecture Courtesy of McGlashan Architecture Courtesy of McGlashan Architecture Courtesy of McGlashan Architecture

From the architect. Type of Project

The Mill Valley Hillside project is a residence for three generations, in two separate dwellings, under one green roof. It brings the grandparents closer to their children and grandchildren, yet carves out spaces tailored to each generation. Upstairs is formal, quiet and dramatic. Downstairs is warm and casual, from cozy window seats to a generous play areas for the boys, their pet rat, and their drum set. As family arrangements evolve, so can the house. The middle level can be shared variously between the two dwellings. Plentiful light, natural finishes, salvaged wood, and built-in elements hand-carved by the architect tie the living spaces together into an organic whole. It is all covered by a green roof, as if the living surface of the hillside was peeled up to create naturally conditioned living space below. With a minimum of disturbance and energy, a steep hillside is sculpted into a thriving family compound.

Courtesy of McGlashan Architecture
Courtesy of McGlashan Architecture

Notable Points

Planning conditions allowed for a single new home with a small 2nd unit on the large hillside parcel. In order for the 2nd unit to expand beyond the allowed 500sf and share space with the upper unit, the architect conceived an attached 3-level structure. To preserve privacy and separation without marring views or limiting outdoor space, each level is topped with a semi-intensive green roof, planted with native and drought tolerant species. Super-insulated, passively conditioned, with many energy- and water-efficiency features, the home is an ecological exemplar.

Cite:"Mill Valley Hillside / McGlashan Architecture" 14 Aug 2010. ArchDaily. Accessed . <>