Real estate developers can be soulless—or so Alan Barr and Bree Dahl had concluded after two years of shopping. Seeking (but not finding) a new townhouse or condo in Brooklyn, Barr, an architect and native New Yorker, and Dahl, an interior designer transplanted from Australia, eventually agreed on Plan B: They would find and breathe new life into a wreck. That was the plan, anyway, until they met local builder Andrew Giancola, who had just completed exactly what they wanted.

Giancola, a guy’s guy who, in the summer, sports cargo shorts and a T-shirt, wasn’t always driven by an eco-minded mission. The third-generation contractor had worked in dry cleaning for nine years before entering his family’s profession. After getting his feet wet with smaller jobs, Giancola made his first investment in a decrepit house in Brooklyn’s South Slope neighborhood in 2003.

By then he had teamed up with architect Caleb Crawford, a partner of Coggan + Crawford Architecture Design and assistant chair of undergraduate architecture at the Pratt Institute. “Caleb definitely put a bug in my ear about sustainable design,” Giancola says. “It didn’t take much convincing, because I wanted to differentiate myself.” In converting the South Slope house to a small apartment building, the two obtained an Energy Star rating thanks to strategies like liberal insulation, argon-filled insulated windows, and power-sipping appliances.

Despite the roadblocks to building green in New York (Giancola says high-quality green construction can cost 40 percent more than standard construction; Crawford can enumerate his run-ins with the city’s building department), the two decided that their next building would outdo the performance of the first one. “Every building is a master class,” Crawford says of his urge to make improvements for each new project.

In 2004, Giancola sniffed out another neighborhood where he could buy cheap and build premium: Bond Street, in a rezoned industrial district on Brooklyn’s Gowanus Canal, a narrow channel of water whose reputation for nasty pollution has only just begun to change for the cleaner. The property, used most recently as an electrician’s warehouse, reflected the neighborhood, Giancola says: “The front was falling off, and a dead body was found two blocks away.” Perfect.

One of the biggest challenges of the project was the building’s footprint, which extended to the very edge of the property. Local building codes prohibit lot-line windows, but Giancola and Crawford wanted to bring daylight into the building. So they performed a little surgery, splitting the structure into two front-and-rear units, each of which is two stories high. “I’ve always been attracted to courtyards,” Crawford says. Barr is grateful for the decision, since it lets morning sun into his and Dahl’s apartment in the rear of the building. He explains, “We work until all hours of the night, so we never see the afternoon sun.”

Other than creating the courtyard and providing the building with a proper street facade made of faceted steel sheets, Giancola and Crawford tried to minimize the transformation. Most of the original interior walls, for example, are exposed to maintain the feel of the building. “The industrial character of the brickwork and the concrete-block insertions are part of the character of the place,” Crawford explains. Preserving so much of the original structure also meant fewer new materials had to be used or shipped.