Spray Foam

Spray polyurethane foam (SPF) is better than any other type of insulation at reducing air leakage.

With foamed-in-place insulation, it is relatively easy to fill wall and ceiling cavities completely. Closed-cell spray foam provides a higher R-value per inch (6.5) than less expensive insulation types like cellulose and fiberglass (3.5 to 3.7).