Attic insulation FAQ

For many open attic floors, air sealing followed by loose-fill cellulose or fiberglass is the most practical approach because it covers irregular framing and tops up existing insulation easily. Batts can work in clear, regular bays. Spray foam belongs in a designed roofline assembly or another job where its air-sealing properties justify the cost and moisture planning.

The main attic insulation types are loose-fill cellulose or fiberglass, fiberglass or mineral-wool batts, and spray polyurethane foam. Rigid foam is also used in specific roof-deck or access details, while older attics may contain materials such as vermiculite that require special caution.

Some older attic insulation can contain asbestos, especially certain loose-fill vermiculite products. The EPA advises homeowners to assume vermiculite attic insulation may be contaminated, leave it undisturbed, and use trained, accredited asbestos professionals when assessment or removal is necessary.