Insulation

There are several types of insulation available depending on your home’s needs:

Batt and Blankets

Insulation Batts and Blankets are made of glass fiber or mineral wool and are most commonly used in new construction or unconfined areas, like unfinished attics, roofs, and under floors. Blankets come in rolls of up to 64 ft.

Batts are simply blankets pre-cut into 4 ft. or 8 ft. lengths. Widths are standard 16 in. or 24 in. making these forms of insulation best for wood framing that uses the same dimensions between studs. Thicknesses include 3 in., 6 in., and 9 in., but a 1 in. version is available for special applications like around sills and narrow spaces inside masonry walls. The R-value for each of these thicknesses varies with the material.

The choice between batts or blankets balances convenience against costs. Blankets are clumsy to install, but if many batts must be trimmed to fit, greater waste results. Batts or blankets are available faced or unfaced meaning they come with or without backing materials made of foil or paper. Backing materials can serve as vapor barriers. Foil backing works well as a vapor barrier, paper not as well unless it has been treated to reduce moisture permeability.

Loose Fill Blown

Blown-in Loose Fill is one of the easiest forms of insulation to install. Commonly made of cellulose, glass fiber, mineral wool, perlite or vermiculite, it can be blown into areas needing insulation. Equipment for blowing insulation into walls or attics can be rented, or contractors with their own equipment can be hired to do the job.

To ensure getting the maximum R-value from the insulating material, watch the density setting used. Properly blown loose fill generally has a higher insulating value per inch than poured loose fill because of the loft added by blowing. As with all insulation types, vapor barriers are often needed.

A new and increasingly popular form of this insulation involves blowing glass or wool fibers mixed with an adhesive into building cavities. The resulting installation cures in a few days, is resistant to settling, and provides effective sealing of the cavities.

Loose Fill Poured

Loose Fill Poured is perhaps the easiest form of insulation to install. Commonly made of cellulose, glass fiber, mineral wool, perlite or vermiculite, it comes in bags that can be poured into areas needing insulation.

For unfinished attics, the material can be poured between joists and spread with a rake. Loose fill pours easily into cavities that are difficult to fill with batts or rigid insulation.

Loose fill has the disadvantage that over time, it settles. This is particularly a problem in vertical cavities such as walls. Taking care to install it at the proper density minimizes this problem. As with all insulation types, vapor barriers are often needed.

Rigid Board

Rigid Boards are plastic foams or fibrous materials pressed or extruded into board-like forms. Common materials include polystyrene, urethane or glass fiber. Polystyrene and urethane have superior insulating qualities, and would therefore make them a better choice than batts or blankets if it were not for their flammability.

When installed inside a house, the boards require an additional covering of a minimum of 1/2 in.-thick fireproof material such as gypsum wall board. Rigid board has the advantages of structural strength, low weight and high R per inch. To achieve an R-30 using glass fiber blankets would require roughly 8.5 in. With rigid urethane boards, R-30 can be attained with only 5.5 in. Rigid boards come faced and unfaced. Some are faced with a reflective material that acts as a vapor barrier and reduces heat flow when facing a dead air space.

Foam

 Foam Insulation, usually urethane, can be injected into wall cavities or sprayed onto roof or floors. Once applied, it expands and sets in about a minute. After it sets, it shrinks slowly for several weeks. Properly applied, shrinkage is less than 5 percent. Like rigid boards, foam insulation has the advantage of high R per inch. Similarly, it shares the disadvantage of requiring a fireproof covering material when installed inside the home.