Discourse about sustainability is often dominated by buzz words such as low-odor, non-toxic, and energy-efficient. Though it's laudable to specify products with these characteristics, their overall impact is limited if other, larger issues aren't resolved first. The Miller/Hull Partnership took this important lesson to heart for the design of this Lake Washington home. The emphasis here was on sensitive site preparation, sensible house orientation, and the surefire basics of passive heating and cooling.
The steep site had an existing house the architects needed to raze and a lush, delicate landscape they wanted to preserve. Limiting the amount of excavation of the hillside was another high priority. So the architects devised a continuous concrete wall to make a platform for the structure's two cantilevered wood-framed cubes and to protect it from landslides. “The reason we did this was to use the site's natural vegetation to hold the hillside,” says Robert Hull, FAIA, who designed the house with associates Brian Court and Petra Michaely. “The cedars, firs, maples, and ferns were left intact.”
That vegetation creates its own cool, forested microclimate to the east, in contrast to the warmth from the western side facing the water. “Heat gain from afternoon sun bouncing off the lake was a real concern,” says Hull, who tries to avoid air conditioning in the predominantly temperate climate in which he works. He found natural ways to cool the house instead, using large, operable windows on the west and a central steel staircase that acts as a “stack” to pull air through the house. “The staircase rises through all three floors, so operable windows up and down the stairs can be reached easily by the owners,” he explains. Automatic shades offer protection from the afternoon sun, and operable sliders and smaller windows provide additional air circulation.
Hull scavenged the teardown house for as much salvage material as possible. And he specified a host of other sustainable materials, including certified red cedar siding, recyclable galvanized and black steel, thermally broken aluminum-clad wood windows, flyash exposed-concrete floors, bamboo-veneer cabinets, low-flow toilets, and energy-efficient appliances. Energy-stingy in-floor radiant heat and an energy-efficient gas boiler keep the interior comfortable on cool nights.
Hull's firm has been doing sustainable design since the early 1980s, and he admits that many of these strategies are merely sound construction practices. “Every architect should be thinking about sustainability,” he says. “I look forward to the day when we don't have to talk about it.”
Lake Washington Residence, Mercer Island, Wash.
The Miller/Hull Partnership, Seattle
Miller & Miller Construction, Maple Valley, Wash.
Quantum Consulting Engineers, Seattle
4,000 square feet