Building Science Corporation
August 31, 2011

This retrofit house is located in Belchertown, MA (Cold Climate). It involved adding R-56 closed-cell spray foam insulation in the rafter cavities and over the face of the rafters. A new 2x4 wood frame wall was added leaving 1” gap from the existing wall and R-32 (5” min.) closed-cell spray foam insulation was installed in existing wall cavities and into the gap beyond. New aluminum-framed storm windows were installed over existing double-glazed low-E wood-framed windows.  3” to 5” of closed-cell spray foam insulation were added to the interior of the existing rim joist and foundation wall. A new basement slab was cast with 2” XPS rigid insulation under the slab.

Enclosure Design


For complete details on this deep energy retrofit project, go to
National Grid Deep Energy Retrofit Pilot Program–18th Century Cape Comprehensive Retrofit