A House Sits Lightly on the Land: To reduce material for construction and energy for use, a house minimizes indoor area and creates an outdoor room that's perfect for enjoying a Southern Californian lifestyle.
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By building less, architect Glen Irani makes his projects do more for the environment. “I try to make everything as light as possible,” he explains, “so I use less material and specify products that require less shipping.” For a married couple with young twins in Venice, California, he designed a house that hovers above a tight 32-by-95-foot lot, creating a 600-square-foot covered outdoor space on the ground floor that can be used for living, dining, and cooking. As a result, he reduced the amount of indoor space to just 2,400 square feet, even though the house rises three stories. (Irani had tried to convince the clients to forgo an indoor living/dining/kitchen area completely, but they agreed to only a 50 percent reduction in the typical size of such a space.) “Outdoor spaces are less resource-intensive than indoor ones” in terms of both construction and operation, states the architect.
The third in a series of “hover houses” designed by Irani, this one offers its residents—an art historian, her filmmaker husband, and their children—a 21st-century version of Southern California's outdoor-focused lifestyle. “We knew Glen from his other houses in the area,” says James Parkos Arnall, one of the clients, “and we liked his sensibility, his approach to building sustainably.” On the ground floor , a galley kitchen and fireplace, along with a dining counter and couches, allow the clients to spend much of their time outdoors. Because the space is mostly covered by the two upper floors, the family can enjoy it even in the rain or on hot summer days. And since the house sits on one of Venice's picturesque canals, raising it above the ground also protects it from floodwaters (and offers great views from the second-story living room and third-story master bedroom).
Irani, who worked for John Lautner, SOM, and Richard Meier and lives on a nearby canal, has developed a deep understanding of the local climate and the way buildings can take full advantage of it. Because it is on the coast, Venice gets more breezes and cooler weather than the rest of Los Angeles. So Irani designed Hover House 3 to capture the wind and draw it up through an open stairwell near the middle of the long floor plate. By providing windows onto the stairwell, a wind tower that rises 9 feet above the roof, and openings on two elevations for every living and sleeping space, the architect ensured that natural ventilation alone would keep the interiors comfortable. Photovoltaic cells mounted on the roof generate 80 percent of the building's energy needs., he states.
A steel-and-wood frame, plus ground-floor walls of locally made, sand-blasted, concrete block, provide the structural bones for the house. Autoclave cement panels enclose much of the building on its long east and west sides, while a garage on the south protects it from the most intense sunlight. The cement panels use less material than other systems, says Irani, and don't create the kind of noise pollution that pneumatic stucco sprayers do. The panels, which are two feet high and come in varying widths, can be easily removed if there is ever a leak behind them, or replaced if damaged. On the north side, large 9-by-10-foot glass panes open the house to the canal. Some of the steel-framed glass panes pivot open, adding a dramatic element of depth and motion to the house's boxy form.
Throughout the house, the architect specified mostly locally sourced materials and ones with no VOCs. Except for paint on the walls, all interior finishes were selected to last indefinitely and eliminate the need for future replacements that might contribute unhealthy emissions. To reduce waste, the contractor made the dining counter on the ground floor with laminated walnut instead of granite, which is heavy and is shipped long-distance. He also used a natural oil to preserve the wood, rather than a petroleum-based oil. And on the roof, he applied tar-free materials. To provide warmth efficiently, he installed radiant, hydronic heating elements in the house's polished cement floors.
Both of the clients work at least part of the time from home, so Irani tucked a pair of offices on the south end of the second floor. On the third floor, he located the master bedroom and two secondary bedrooms. To take advantage of the great canal views he built a deck on part of the roof, which also provides easy access to the PV panels for cleaning and servicing.
The indoor stair leading from the second to the third floors offered the architect a chance to inject a dash of color and structural dynamics. Tomato-red walls combine with metal treads bolted to a structural glass balustrade to create a dramatic element at the heart of the house.
“I don't think about green strategies or sustainable design,” says Irani. “It's just good design.” He also states that until cities and towns reform their building codes to require more efficient construction, “we can't really say we're being sustainable.” He explains, “Building codes require way too much concrete, way too much steel. Right now we're just kidding ourselves if we think we're being green.”
Irani hopes that his Hover Houses serve as prototypes for a different kind of living in places such as Southern California, where a temperate climate allows people to spend much of their time living, cooking, and entertaining outdoors. By creating attractive outdoor rooms, these houses show they can do more with less.