Blown In Cellular. This Old House
Faved vs Unfaced Insulation: Faced insulation includes a built-in vapor retarder (kraft paper, foil, or plastic) to block moisture and simplify installation in exterior walls, while unfaced insulation lacks this barrier, making it ideal for adding layers in attics or where moisture is not a concern. Faced costs slightly more ($0.50-$2/sq ft) compared to unfaced ($0.50-$1.75/sq ft).
Key Differences:
Vapor Barrier: Faced insulation features a kraft paper or foil backing that acts as a vapor retarder, protecting walls from moisture. Unfaced insulation has no backing.
Installation: Faced insulation often has stapling flanges for attaching to studs, making it easier for new installations. If using faced insulation, the paper side should face towards the warm-in-winter side of the room (usually toward the living space) to prevent trapping moisture. Unfaced is better for fitting into tight or irregular spaces.
*Faced: Exterior walls, basements, and crawlspaces where moisture control is needed. Cost more than unfaced.
*Unfaced: Attics (as a second layer), soundproofing interior walls, or when a separate vapor barrier is already installed. Cost less than Faced.
*Fire Rating: Unfaced insulation is generally more fire-resistant. Kraft-faced insulation is flammable, while foil-faced is non-combustible.