Kraft-faced Fiberglass Batt Insulation

Fiberglass batt insulation is a thermal insulating product with high thermal performance, moisture resistance, fire resistance, and is sound absorbent. Fiberglass insulation is fabricated using a molten glass batch consisting of raw materials (sand, borates, soda ash, lime) and recycled glass cullet. The molten glass is spun into fibers and an atomized binder is applied as the fibers settle onto a conveyor to form batts which are then conveyed through an oven to cure the binder. Originally phenol-based formaldehyde binders were used, but concerns over indoor air quality led fiberglass batt insulation manufacturers to transition to formaldehyde-free binders. The entire industry in the USA and Canada switched to formaldehyde-free binders by 2015 for lightweight fiberglass products. (Note that high density fiberglass insulation, outside the scope of this CP, may still use formaldehyde-based binders.) Fiberglass batts can be either unfaced or faced with a Kraft paper, foil-scrim-kraft (FSK), or polypropylene-scrim-kraft (PSK). This common product applies to fiberglass batts with standard kraft paper facing, which is the cheapest vapor retarder option. The facing is typically bonded to the fiberglass via an asphalt coating on one side of the kraft paper. This coating may contain fungi growth inhibitors and plant-based odor suppressants, although these additives were not found to be common. Fiberglass batt insulation is installed by placing the batts into the wall cavity and stapling the facing to the framing members. Faced insulation should not be left exposed, but covered with gypsum board.

A historical version of this Common Product is available here: https://pharos.habitablefuture.org/common-products/2202612