His $5 Million Experiment: Building a Very Big House With Very Little Carbon

By the time he was 50, Walter Cain had made enough money as a partner in a private-equity firm to retire and, he says, “do something creative for the rest of my life.” Meanwhile, restoring and enlarging an 1837 Greek revival house in Piermont, New York, along the Hudson River, had reinforced his love of buildings. 

So at 52 he enrolled in Columbia University’s Graduate School of Architecture, Planning and Preservation. There, one of his professors was David Benjamin, an architect who studies buildings’ carbon emissions, particularly emissions associated with construction. Processes that include mining limestone, sand, clay and iron ore and using them to form materials like concrete, glass and steel, and transporting and installing those materials, release large amounts of carbon into the atmosphere—the building’s so-called “embodied carbon.”