Renewal Design-Build was blessed with a green remodeler’s dream: a Decatur, Ga., couple eager to renovate their home as sustainably as possible. But even with free rein to go green, the project still had its challenges: Transforming the 1930s-era single-story bungalow into a two-story EarthCraft-certified home meant navigating a tight lot and a small footprint, all while working around several remaining pieces of the original structure.

The project’s mission was a familiar one for remodelers: Expand the two-bedroom, 940-square-foot house into a space large enough to accommodate the owners’ soon-to-be-growing family. Not as common was the husband’s extensive knowledge of green building practices and willingness to use costlier technologies that offer long-term payback. “It was a great commitment beginning with the home­owners who sought out an architect who was very conscious and knowledgeable about green design and a contractor who was equally committed,” says Renewal project manager Lisa Manka.

Though completely razing the building would have been the easiest route, Renewal opted to keep as much of the foundation as was structurally possible, as well as the home’s only bathroom, its front porch, and a recently added composite deck on the rear.

These constraints, combined with the 50-foot lot width, limited architect Eric Rawlings primarily to an upward expansion within the confines of the existing footprint, save for an extra 100 square feet added to the back. Even with an extra story, Rawlings had to be creative to meet the design parameters including four bedrooms and two additional bathrooms.

Aside from a guest room, the structure’s first floor favors open space, letting traffic flow through the main living room instead of hallways. Rawlings also minimized circulation area on the second floor and eliminated unnecessary space.

The design incorporates strips of clerestory and high-set casement windows to enhance daylighting and increase ventilation while still providing privacy. Overhangs shade many of the windows; a 9-foot cantilever on the second floor shades the lower level of the east-facing side, where windows were kept larger to maintain the home’s principal view.

The tight lot also necessitated careful planning of deconstruction to accommodate the installation of EarthLinked Technologies’ geothermal heating and cooling, a homeowner-requested feature Renewal was specifying for the first time. Once one side of the house was removed, geothermal contractor HP Building Solutions maneuvered compact equipment into the footprint to drill 100-foot wells for the geothermal tubes. By completing this task while the original roof was still in place, mud was contained.

Following the geothermal installation, Renewal dismantled the rest of the original structure, keeping most of the foundation footings and some of the hardwood flooring in tact, as well as the first-floor bathroom—whose tarp-protected shell protruded noticeably until the new walls went up. Unpainted wood was turned into mulch for flowerbeds and to protect the driveway during construction; brick footings that needed to be replaced were ground up and used for soil amendment.

HP also was responsible for building the home’s new shell with Global Building Solutions structural insulated panels (SIPs); Icynene foam was sprayed along the roofline and under the subfloor.