Types of Insulation

Loose fill. Fiberglass and cellulose are the most common loose fill materials. Loose fill is preferred by insulation contractors for finished wall spaces, attics, and hard-to-reach areas, because it can be blown in. This type of insulation is relatively inexpensive, and many cellulose-based varieties are made with up to 80 percent recycled materials. Loose fill insulation is often used to retrofit older homes. One drawback of loose fill, however, is that there can be some settling of the material, particularly when dry installation methods are used. However, the stated R-value of the material will reflect its effectiveness after the settling has occurred.


Spray Polyurethane Foam. Spray Polyurethane Foam (SPF) is a mixture of two components that form a dense but expanding material, which can be sprayed into walls and crevices, on concrete slab, or on the interior side of wood sheathing. The foam is highly mold-resistant, cannot be damaged by water, and can easily be injected into irregular spaces. The foam also meets air barrier requirements in building codes, without the use of additional materials.

SPFs are usually classified as either an open-cell foam or a closed-cell foam. Closed-cell foam is stronger and has a somewhat higher R-value than open-cell foam. Because of its higher density, much more of the material can be needed to complete certain types of projects, thereby significantly increasing cost. In many instances, open-cell SPF can still provide the same insulating and vapor-controlling properties.

One downside of spray foam insulation is that the initial cost is significantly higher than most other insulation materials. Also, the foam will tend to lose a little of its R-value over time; however, the decline stops when the spray foam achieves equilibrium with the surrounding environment, and its R-value will still remain very high compared to other types of insulation.