This retrofit house is located in Quincy, MA (Cold Climate). It involved building an additional floor and a new unvented roof with two layers of 2” foil-faced polyisocyanurate rigid insulation above the roof deck and 10” open-cell spray foam insulation in the rafter cavities. The walls were retrofitted to add two 2” layers of polyisocyanurate rigid insulation to the exterior of the wall sheathing and open-cell spray foam insulation in the framing cavities. The windows were replaced and open-cell spray foam insulation was added to the interior of the rim joist. Minimum 2” of closed-cell spray foam and a 2x4 wood frame wall with fiberglass cavity insulation were added to the interior of the field stone foundation wall. A new basement slab was cast with 2 ½” EPS insulation under slab.
For complete details on this deep energy retrofit, go to
National Grid Deep Energy Retrofit Pilot Program–Retrofit and Addition to 1905 Bungalow