Numerous types of insulation, including blanket, concrete block, foam board, loose fill and sprayed foam, are available as of 2015. Each type of insulation comes in a variety of R-values, which measure the insulating material's resistance to heat flow.
Blanket insulation comes in batts or rolls. It can be made from several materials, such as fiberglass, rock wool, slag wool or plastic fibers. A number of natural fibers can be used as insulation, including cotton, hemp, straw, wool and cellulose, which is typically made from recycled paper. Some of the uses of blanket insulation include insulated unfinished walls, floors or ceilings, where it is fitted in between the joists, studs or beams. The recommended R-value for batt insulation depends on the application and the type of material used. For fiberglass batt insulation, the R-value ranges from 11 for a 3.5-inch thick batt to a value of R-38 for a 12-inch thick batt.
Several different ways to insulate concrete blocks and walls include filling them with insulation, or installing polyurethane foam board insulation over the interior or exterior of the wall. Many homes use loose fill fiberglass or cellulose insulation, which is blown into walls and attics using a special machine.