Maine builder, designer, and Passive House consultant Chris Corson is passionate about reducing the environmental cost of America’s houses — both new and old. Corson’s first Passive House project was profiled in the May and June, 2012, issues of JLC. This year, Corson’s crew is applying a similar method to an existing home in Newcastle, Maine, aiming to turn the old house an air-tight, superinsulated modern dwelling. Here’s a step-by-step look at EcoCor’s technique.