Loose-Fill Ceiling Insulation

Types

• Loose-fill insulation is composed of tiny particles of foam, fiber and other materials that make it fire and moisture resistant. These particles form a material that can be blown into any space without harming structures or fixtures. The most common materials used include cellulose, fiberglass and mineral wool (rock or slag). These are produced from recycled materials. Cellulose is made from recycled newspaper and fiberglass typically contains around 20 to 30 percent recycled glass. Mineral wool loose fill insulation is made from 75 percent recycled materials. Less common materials used for loose-fill insulation include polystyrene beads, vermiculite and perlite. Cellulose and mineral wool are denser than fiberglass, and therefore have more resistance to airflow.

R-Value

• A material's insulating capacity, or its resistance to heat flow, is called its R-value. The higher the value, the better the insulating capacity and the less amount of material is needed to prevent heat loss. For example, experts recommend loose-fill insulation with an R-value of 38 (R-38) for ceilings. Cellulose settles more than fiberglass or mineral wool, which causes a loss in R-value. Manufacturers are required to show the settled thickness on the bags of insulation clearly on the package. This is usually stated as "installed thickness."

Fire and Moisture Resistance

• Fiberglass and mineral wool insulation is naturally fire resistant, but cellulose is treated with chemicals to make it fire resistant as well. Moisture resistance is also important because most homes have water vapor that moves up to insulated cavities. Moisture reduces the insulation's R-value. Fiberglass and mineral wool can absorb about 1 percent of their weight in water vapor and cellulose absorbs 5 to 20 percent. Most types of insulation can absorb large quantities of water if exposed to high humidity. If the insulation is exposed to water from a leaking roof only once, it should dry and regain most of its R-value. Loose-fill insulation that is repeatedly soaked will lose most of its R-value permanently.

Installation

• Loose-fill insulation is installed in your ceiling using equipment that blows it into the cavity. Typically, two holes are drilled. The holes are spaced vertically between the rafters and are about 2 inches in diameter. The insulation is blown into the holes and then the holes are sealed. Installation is best done by professionals to ensure that the proper amount of insulation is blown in and to avoid voids or gaps in the corners of the ceiling.

Precautions

• Inhaling fiberglass particles or the fire retardants and insecticides in cellulose insulation is hazardous and can make you ill. When installing loose-fill insulation of any type, wear protective eyewear and clothing as well as a respirator. Minimize contact with the insulation by wearing long sleeves and pants. Before installing, seal all ductwork and any openings where particles could leak into the wall or your living space.