Blown Insulation vs. Faced Batt Insulation

Blown-In Insulation

• Blown-in insulation is made of several different materials. Cellulose, cotton, fiberglass and mineral wool are all suitable for attic spaces and wall interiors in dry, above-ground areas. Several plastic foam compounds are used for insulation. Of these, polyurethane is suitable for blowing into areas that may occasionally be damp.

Advantages and Disadvantages

• Blown-in insulation can fit easily into irregular spaces like attics or under eave spaces. It can be sprayed damp on wall surfaces before interior finishing materials like sheet rock or drywall are installed. Dry, it can provide loose fill between rafters. Air spaces between particles of blown-in insulation amplify its R (heat-reduction) factor, making it an excellent insulator for areas that are only infrequently open or accessible for entry. Unless netted or covered, however, loose fill remains loose, making it a poor choice for areas with strong ventilation fans or other sources of air movement. Loose insulation becomes clotted and difficult to deal with if it gets wet. The job is most often professionally done; do-it-yourselfers will find themselves dealing with expensive equipment and respiratory-protection issues.

Faced Batt Insulation

• Faced insulation batts are available in fiberglass, cotton, cellulose and mineral wool. Batts are covered (faced) on one side with craft paper or foil-covered paper. Available in several standardized widths, faced batt insulation is best suited to regular spaces with easy access. Rolled batts are bulky but relatively lightweight.

Advantages and Disadvantages

• Faced batt insulation is best suited to regular spaces with easy access. Homeowners can manage batts alone or with a little assistance, and batts are easily fitted between rafters in many attics, both on the floor and ceiling. During renovation, batts can be easily and quickly installed between studs before interior wall finishing. Properly anchored, they will remain in place without settling. Few tools are needed, and batts can often be cut with scissors. Facing provides a vapor barrier, although you will need to check with your building department to be certain that the batting you want meets code requirements. There are questions about flammability of batt facing; craft paper has been substituted for formerly asbestos-treated coverings.

Choosing the Right Material for Your Insulating Job

• Selecting the most suitable insulation material means balancing several variables. Fiberglass is the most popular do-it-yourself insulation because of low cost, although green homeowners and others express concerns about a formaldehyde by-product of fiberglass deterioration. Cellulose and cotton batts emit few or no gases with aging, but installation costs are higher, especially for cotton. Even small or intermittent leaks or damp spots can be problematic when insulating and should be repaired before any insulation is installed. If you are hiring an insulating contractor, check references and licensing to be certain that you will receive the amount and quality of insulation you are paying for.