The original BIBS insulation consists of adhesive-coated white fiberglass loose-fill fibers that are blown into wall cavities and retained by a lightweight polypropylene netting that is typically stapled to wood framing studs. Double-sided tape or special hooks are used for attaching the netting to metal stud framing. The netting is slit with a utility knife where necessary so that the installation hose will fit through to the area to be filled. Wall cavities are then filled with insulation through a hose connected to the “heart” of the system, a patented high-pressure machine called “the big blower.” A thin mist of latex binder blends with the fiberglass at the blower to prevent the fiberglass from sagging. Insulation is added to the wall cavity until the netting bulges out about 1 to 1V2". The fibers will compress beneath the gypsum wallboard to achieve the proper density and R-value (Fig. 9.7).
The Blow-In-Blanket System completely fills the wall cavity, including all wiring and fixtures, while eliminating voids and air gaps. Tests conducted by the National Association of Home Builders’ (NAHB) National Research Center show that the Blow – In-Blanket System reduces air infiltration by up to 68 percent over conventional batt-type insulation. (This may not be as dramatic as it appears, since tests show that wall insulation is insignificant in controlling air leakage; gypsum wallboard is a much bigger factor.)8
The BIBS insulation has a resistance to settling and drifting. When installed correctly, BIBS insulation provides a uniform density even in hard-to-insulate sidewall areas. Typically installed using a two-person crew, BIBS insulation can be used in renovation and new construction for either wood or steel stud framing systems.