Resources

"The most common insulation, fiberglass, does not stop air leakage. In older homes, dirty fiberglass is a telltale sign of air movement (it simply collects dirt like a filter). Certain types of insulation, such as dense-packed cellulose and certain foams, can be effective at reducing air flow as well as heat flow." Prepared by the Office of Building Technology

"Closed-cell spray polyurethane (ccSPF) foam air barriers also offer wind-load resistance, seamless or “monolithic” construction and almost zero air permeability, according to building-science experts. The product conforms to unusual shapes and fills in voids common in building enclosures and is rigid, self-supporting and fully self-adhering."

"You can greatly reduce the air leakage by blowing high-density insulation or injecting spray foam insulation into these joints, thus reducing these energy-gobbling air paths." Prepared by the Department of the Environment