Fiberglass consists of extremely fine glass fibers – one of the most common insulation materials. It is commonly used in two different types of insulation: blanket (batts and rolls) and loose-fill.
Cellulose insulation is made from recycled paper products, primarily newsprint, and has a very high recycled material content, generally 82% to 85%. The paper is first reduced to small pieces and then fiberized, creating a product that packs tightly into building cavities and inhibits airflow.
Made from polyurethane, this product reduces air leakage better than any other type of insulation. It fills the nooks and crannies of unusually shaped building cavities easily. There are 2 different types of spray foam.
* Closed-Cell : Closed-cell spray foams provide a higher R-value per inch than less expensive insulation types like fiberglass, cellulose or open-cell foam, all of which have R-values of R-3.2 to R-3.8 per in. Closed-cell spray foam is the most expensive residential insulation. When installed well, however, it performs better than any other insulation. It is an excellent air barrier, is impervious to moisture, and is an effective vapor retarder. Because of its density and gluelike tenacity, it also adds structural strength to a wall, ceiling, or roof assembly. To seal air leaks in retrofit applications as well as new construction—for example, at rim joists or the attic side of partition top plates—closed-cell spray foam is an extremely useful material.
* Open-Cell : The low density of open-cell foam makes it relatively vapor permeable (a 3-in.-thick layer of open-cell foam has a permeance of 16), so when it’s used to create an unvented conditioned attic in a cold climate, the interior face of the foam should be covered with a vapor retarder. This can be accomplished by spraying the cured foam with vapor-retarding paint. Open-cell foams use water or carbon dioxide as the blowing agent. Some open-cell foams are made in part from bio-based raw materials—for example, soybean oils—in place of a portion of the petrochemicals. Like closed-cell foam, open-cell foam creates an effective air barrier. Unlike closed-cell foam, however, open-cell foam absorbs and holds water, has a lower R-value per inch, and is vapor permeable. The permeable nature of open-cell foam can be a virtue or a drawback, depending on the application.
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