The following is an excerpt from "The Green House: New Directions in Sustainable Architecture" by Alanna Stang and Christopher Hawthorne (Princeton Architectural Press, 2005). The excerpt is from the section "Suburb."
Charlotte, North Carolina, a banking center and one of the fastest growing cities in the southern United States over the last couple of decades, has a population of more than half a million. But you’d never know it from looking at the five acre piece of land for which the Charlottesville, Virginia firm William McDonough + Partners — long a leader of the green design movement — designed this two-story, three-bedroom house. Though the house sits within the Charlotte city limits, its rustic exterior finishes and sprawling, leafy grounds make it seem much further removed from urban life than the twenty miles that separate it from the heart of downtown.
“The site is essentially a hundred-year-old forest,” says Allison Ewing, the McDonough + Partners architect who led the design team. The property is dominated by stands of loblolly, or yellow southern pine trees, which grow thin and tall — up to 100 feet, in some cases. On this site, they’ve woven their branches together over time to form canopies that provide shade and an always-shifting variety of light patterns.
“We asked the client when they hired us to get a survey done,” Ewing adds. “Not just the site contours but a real tree survey. That identified the key, really beautiful trees we wanted to design around.”
Positioning the house along axes already defined by the existing trees was the firm’s first step in defining sustainability on this particular project. “Bill talks all the time about how and when we become indigenous to place, native to place, ourselves,” Ewing says, referring to William McDonough, the firm’s founder. In addition to running his thirty-person firm, McDonough is a noted author and frequent lecturer on sustainability and a partner in the design and consulting firm MBDC, which advises companies, including multinational corporations such as Ford, about how to design and produce without waste, or according to the principals of what he has termed “cradle to cradle” design.
For the Charlotte house, it wasn’t just a matter of knocking down as few trees as possible during the construction process. The architects aimed, from the outset, to create interior spaces that would mimic the experience of standing outdoors on the site. They also designed a vaulted roof above the main living areas to suggest the expansive sense of a canopy rising above.
“When you get right down to it, we think people deep down would rather spend their days outdoors,” Ewing says. “So we try to create architecture that gives them that feeling.”
Other features of the design pointed toward the same experiential goal. The ground floor is generally open and fluid in plan, with high cabinets helping to divide the space and broad expanses of low-emission windows for abundant light. Two fieldstone walls, perpendicular in plan, run through the center of the L-shaped house.
“Originally the client came to us saying they wanted a stone house,” Ewing says, “but a house entirely of stone was going to be prohibitively expensive. We felt we could give them the sense of having a stone house by combining wood and glass with the prominent stone walls.” The walls within also help ground the house in a firm horizontality, drawing the eye back outside, in what Ewing calls “a key element in integrating the house with the landscape.” Also important in reaching that goal was the firm’s work with the landscape designers on the project, Nelson Byrd Woltz.
The result of that constant emphasis on marrying house and site is what Ewing calls “both an anomaly in its urban setting and an archetype: a home in the woods.”
And since this is a McDonough + Partners house, the green elements don’t end there. A geothermal system, which taps into the heat of the earth by digging several hundred feet down into the ground, provides radiant heat. (Because of high installation costs and because few residential builders have experience working with them, geothermal systems remain a rarity in single-family homes, even those that aspire to high levels of green design.) All the wood used in the house is either reclaimed, like the eastern white cedar siding, or certified as sustainably harvested. The trees, not surprisingly, offer good shading in the summer, aided by deep roof overhangs. In winter there is good heat retention from passive solar orientation, though Ewing says that “we weren’t dogmatic about orienting the house directly to the south. It was a synchronicity between passive solar and the views.” In addition, no formaldehyde or vinyl was used, and all the materials are non-toxic and were bought locally where possible. The walls are made of SIPS panels, a super-efficient building material that sandwiches a polystyrene core between two layers of oriented strand board, or OSB.
Still, every architect at McDonough + Partners would tell you that green design fails the minute it becomes a mere checklist. “We try to define sustainability as broadly and holistically as possible,” Ewing says. “You can figure out a million green features, but in the end it’s about the clients, how they live, and their health and well-being.”