Loose-fill insulations are well suited for places where it is difficult to install other types of insulation, such as irregularly shaped areas, around obstructions (such as plumbing stacks), and in hard-to-reach places. They can be installed in either enclosed cavities such as walls or unenclosed spaces such as attics.
Blown-in loose fills are particularly useful for retrofit situations because, except for the holes that are sometimes drilled for installations, they are one of the few materials that can be installed without greatly disturbing existing finishes. Rock wool or slag wool loose-fill insulation is often used for insulating existing walls and ceilings in mobile homes.
In most new construction, however, the more common choices in insulation are batts or rolls because they can be installed without the use of special equipment before walls are finished. Batts are available in standard widths designed to match the cavities created by wall studs. Loose fills are sometimes used in new construction, though. A mixture of loose-fill insulation and an adhesive can be sprayed into wall cavities before the walls are closed. Such methods may result in fewer gaps in the building’s thermal envelope than can occur with batts.