This retrofit house is located in Westford, MA (Cold Climate). It involved rebuilding the roof to convert the attic into living space using closed-cell spray foam insulation in the rafter cavities. The walls were retrofitted to add two 1 ½” layers of polyisocyanurate rigid insulation to the exterior of the existing plywood sheathing. The existing fiberglass batt insulation in the framing cavities was left in place. The windows were replaced and open-cell spray foam insulation was added to the interior of the rim joist. Closed-cell spray foam insulation was added to the interior of the foundation wall and the slab was left uninsulated.
Enclosure Design
For complete details on this deep energy retrofit project, go to:
National Grid Deep Energy Retrofit—Westford Modern Colonial Retrofit