Vermiculite, a mica, is used as a loose fill attic insulation and as an insulator within concrete block and hollow wall construction. The group of foams known as cellular plastics includes expanded polystyrene, extruded or molded polystyrene, polyurethan, and polyisocyanurates. Expanded polystyrene that is used for foundation insulation, exterior sheathing, and sidings should not be exposed to sunlight or moisture over a long period of time. Extruded polystyrene, which is manufactured as Diversifoam, Certifoam, Dow Styrofoam, and similar products, is used for many roofing, foundation, and subsoil applications. Polyisocyanurates are used on exterior walls and for roofing systems.
Polyurethane is a foam that is blown into wall cavities.
Forms of Insulation Four common forms of insulation are batt and blanket, loose fill, rigid, and foam. Some insulating materials are manufactured in more than one form. Selecting which insulation form and material to use depends on the specific application and the cost. Batts and blankets, which are made from fiberglass or mineral wool, are the most common forms of insulation. They are designed to fit within conventional framing and are available in a variety of thicknesses.