Insulation should be installed carefully in an existing home or attic as well as in newly constructed buildings. Before choosing whether to purchase blown-in insulation or roll insulation and how much to buy, determine how much insulation is already in your installation area, if any. In addition, make sure you have personal protective equipment, such as goggles, a dust respirator, a long-sleeved shirt and pants, and gloves, to protect yourself from insulation materials, which can irritate the skin.
Roll insulation, which also is called blanket insulation or batt insulation, is a flexible product created from mineral fibers such as rock wool or fiberglass. Professionals or do-it-yourselfers can install roll insulation. It comes with or without vapor-retardant facings made of brown paper or foil. Some roll insulation is wrapped in plastic for easy handling.
Blown-in insulation is also called loose-fill insulation and comes packaged in bags. This type of insulation is made of rock wool, fiberglass, vermiculite or even cellulose in the form of many fiber pellets or loose fibers. Professionals use pneumatic equipment to blow the insulation into wall cavities or unfinished attic floors. They also can mix insulation made of fiberglass or cellulose fibers with foam or an adhesive to keep it from settling in a new home's wall cavities after it is installed.
Benefits of Blown-In
A chief benefit of blown-in insulation is that it is easy to use to fil in irregularly shaped areas. Roll insulation is not as convenient to use in this situation. For example, you must hand-cut or trim roll insulation to make the pieces fit in places where joist spacing is not standard. This includes areas near corners, doors or windows. In addition, you must hand-trim roll insulation to fit it in spots in walls with obstructions such as pipes, electrical outlet boxes and wires. Blown-in insulation is quicker to install and offers better coverage. In addition, roll insulation typically is more expensive to install than blown-in insulation is. Where common fiberglass roll insulation might cost 38 cents per square foot, blow-in cellulose insulation would be about 17 cents per square foot, according to an online report from This Old House magazine.
Benefits of Roll
Roll insulation is available in widths to match standard spacings of floor and attic joists and wall studs. This can make the insulation process relatively simple. Both roll and blown-in insulation can be fire- and-moisture resistant, which is helpful in places where insulation is exposed, such as in basement walls. However, keeping loose blown-in insulation fibers away from ventilation and light fixtures can be a little trickier than keeping roll insulation from these spots.
The R-values -- which indicate insulating effectiveness -- between blown-in insulation and roll insulation are the same. Roll insulation typically is 2 inches to 3 inches thicker than blown-in insulation to achieve the same R value, but both insulate equally and are durable. To achieve the indicated R-value, both types of insulation must be installed correctly.
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