Tightening Up a Two-Family House

Because the original balloon-framed walls had never been insulated, dense-pack cellulose was easily blown into the empty stud cavities from the exterior.

Energy-efficient casement windows were cantilevered beyond the original rough openings, secured with metal ties, then surrounded with snug-fitting rigid foam, which also serves as the wall’s drainage plane.

The roof framing in the attic mechanical room is encapsulated in a thick layer of closed-cell spray foam, bringing all the hvac equipment and ductwork within the building’s thermal envelope. Plywood panels, fastened to blocking before the foam was applied, provided solid mounting surfaces where needed. To meet the fire code, the exposed foam was coated with intumescent paint.

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