This hillside house sits on a very steep, physically constrained, and visually sensitive ¾ acre lot at the edge of the Marin headlands open space just north of the Golden Gate Bridge. Summer fog is common, but on clear days there are panoramic views of Tiburon to the north, the entire expanse of San Francisco Bay to the east, and the city to the south. Substantial retaining and support walls were necessary for vehicle access and fire engine turn around and all combined to determine the location and footprint of the house.
The three levels of the 4000 SF house/770 SF garage step down the hillside approximating the natural slope. The garage, living areas, and master bedroom are on the entry level with kids’ bedrooms and family room on the lower level and two offices on the upper most level. Because the predominant orientation is easterly a strategy to prolong direct sunlight reaching the interior was necessary. Sloping much of the glazing back overhead to capture direct noon and early afternoon sunlight results in chamfered forms which fortuitously help the house visually assimilate to the site as do its earth covered roofs. Additional living/dining/kitchen light is provided via a long narrow skylight along a westerly wall of reflective corrugated sheet metal. Excess heat built-up on clear, sunny days is bled off with a pair of third level ventilation chimneys.
Design ChallengeThe challenges for this residence were almost entirely site related. The major issues being:
- The only access was via an existing narrow driveway so vehicle access, fire engine turnaround (required), and house locations were essentially predetermined.
- The extremely steep slope (1.5:1) allowed only limited possibilities for cut and fill.
- An easterly orientation and common early morning fog made access to direct sunlight a major priority.
Physical ContextNotable ways in which this project responds to the physical context include:
- The single access point and steep slope (1.5:1) made cut and fill prohibitively expensive and virtually dictated the use of a stepped three tier plan. Roof planes are covered with 12" of earth and planted.
- The steep easterly slope and common early morning fog made access to direct sunlight a major priority. By sloping most of the glazing back overhead direct sunlight can enter the interior up through early afternoon. A 57 foot long continuous slot skylight along a westerly wall of reflective corrugated sheet metal provides main floor backlighting as well as supplemental sunlight.
- The hillside is visually sensitive as seen from the town below and in response the house form parallels the steep slope with its champhered forms. Exterior finishes include gray corrugated metal (blending with the pervasive fog), wood slats (accommodating seasonal expansion and contraction), and earth covered roofs.
- The project responds to the 180 degree view of San Francisco Bay via a band of panoramic glazing.