The design/build architects of Raleigh, N.C.–based Tonic Design are big on the synergies afforded by their way of producing buildings. Interweaving design and construction creates opportunities for improvisation, says principal designer Vincent Petrarca. “It’s like jazz.” The LEED for Homes–certified GREENville House in Greenville, N.C., demonstrates the power of such synergies, not only between design and construction, but also between modernism and sustainability.
The owners envisioned the house as an alternative model for their architecturally conservative community, Petrarca says. They favored modernist design, “and they had researched solar and geothermal from the beginning.” They also planned the house as a long-term family residence, and one of their requirements—children’s bedrooms on the second floor—influenced the building’s pinwheel-like footprint. The two-story section “creates a lot of shadow,” Petrarca notes. To maximize solar exposure, “the building stretches away from itself.” Petrarca and project designer Katherine Hogan developed a system of aluminum rooftop “trays” that support photovoltaic and solar thermal panels and turn down at the roof’s edge for window shading. (Solar thermal collectors supply the house’s hot water; when completed, the photovoltaic array is projected to meet 60 percent of its electrical load.) The house’s low-maintenance shell combines brick-, red cedar-, and zinc-cladding in an interlocking composition that blurs traditional distinctions among foundation, walls, and roof.
Features such as sustainably harvested woods, a geothermal heat pump HVAC system, and rainwater harvesting presented a learning opportunity for subcontractors unfamiliar with LEED—or with the EPA’s Energy Star and Indoor Air Plus programs, with which the project also complied. “Our cabinetmaker will now offer, to us and to any other customer, a ‘LEED option’ with low-VOC finishes and sustainable woods,” Hogan reports. “The HVAC company, the plumber, the landscape installer … everyone who worked on the project can now say they’ve done a LEED house. It becomes transformative.”
