In older homes, specifically, asbestos may be found in many different materials, from pipe insulation to flooring adhesive to roof shingles. One of the most common materials containing asbestos fibers is attic and wall insulation. But just because your insulation is old doesn’t mean it is dangerous. Some materials that suspiciously look like they should be asbestos really aren’t asbestos. A quick visual inspection can tell you whether or not you should get your insulation tested for asbestos.
What Is Asbestos Insulation, and Why Is It Dangerous?
It’s estimated that homes built from 1900 and throughout the 1980s contained insulation that was made with asbestos. Asbestos insulation was favored because it was strong and fireproof. The insulation was used for all types of purposes, including insulating walls, floors, pipes, ductwork, and boilers. It was also used to fireproof structural beams. The insulation can become a danger in the home, typically during renovations and repairs when it is moved, removed, or damaged. The movement of the insulation will cause toxic asbestos fibers to become airborne and potentially inhaled by occupants in a residence.
Types of Asbestos Insulation
Spray-on Insulation
Spray-on insulation was used in commercial buildings and could be spotted as a thick layer of gray material on the ceiling. This insulation is made up almost entirely of asbestos. When it is disturbed or damaged, asbestos fibers become airborne.
Loose-Fill Insulation
Loose-fill insulation is fluffy and is almost completely made up of asbestos. It was known as “asbestos attic insulation” and was placed on an attic’s flooring. It was also blown into a wall’s empty spaces. Since it’s loose, any air current or breeze can send asbestos fibers into the air that can be inhaled.
Block Insulation
This type of wall insulation looks like boards and they are made entirely of asbestos. When these asbestos insulation boards or blocks are sawn apart or manipulated in any other way, asbestos is released into the air.
Blanket/Wrapped Insulation
This insulation was made of asbestos and covered pipes and plumbing and was also known to cause health problems on Navy vessels. Very old wrapped insulation can easily crumble releasing asbestos dust into the air. Another type of dangerous blanket wrap, called asbestos wool insulation, was also used for pipes and releases asbestos fibers as this woven type of fabric ages.
Insulation That May Contain Asbestos
The two main types of asbestos-containing insulation commonly found around the home are vermiculite insulation and asbestos pipe insulation.
Vermiculite Insulation
The types of insulation that were most commonly made with asbestos are loose-fill, also called blown-in, insulation. Loose-fill insulation comes in a variety of materials. It is easy to identify by its loose, lumpy form and fluffy or granular texture. Loose-fill never has paper or other types of backing, like some (but not all) batt and blanket insulation does. If you determine that your attic or walls have loose-fill insulation, the next step is to determine what type of material it is, as only some types may contain asbestos. Vermiculite loose-fill insulation is one of the most common household materials that contain asbestos. Vermiculite insulation has a pebble-like appearance and typically is a grayish-brown or silvery-gold color. It is made from a natural mineral material that is mined from the earth. The mineral expands when heated, creating the lightweight and somewhat stony-looking particles that make up the insulation. In the United States, most of the vermiculite insulation containing asbestos was sourced from a mine near Libby, Montana, which was active until 1990. The raw vermiculite material taken from the mine was contaminated with asbestos. Insulation made from this material represents over 70 percent of the vermiculite insulation found in U.S. homes. Because the Libby mine closed in 1990, houses built or remodeled before that date might have asbestos-containing insulation. If the house was built after 1990, the chance that your house has asbestos-contaminated insulation is reduced but not eliminated.
Asbestos Pipe Insulation
Pipes in basements, furnace rooms, utility rooms, and other service areas within the home may be wrapped with insulation that contains asbestos. Pipe insulation looks like corrugated cardboard or paper and is an off-white or gray color. The insulation will be fully wrapped around the pipes, often with an outer casing to hold the insulation on the pipes. The corrugated edge of asbestos pipe insulation is usually the red flag that this does, indeed, contain asbestos. If the pipe insulation were fiberglass, you would see tufts of fiberglass sticking out of the edge.
Insulation That Does Not Likely Contain Asbestos
Common forms of household insulation typically do not contain asbestos and are considered to be safe: batt or blanket fiberglass insulation, cellulose insulation, loose-fill insulation, and rock wool insulation.
Batt or Blanket Insulation
If your attic or wall insulation is in batt or blanket form, whether it’s fiberglass, cellulose, or another material, you generally don’t have to be concerned about asbestos.
Cellulose Insulation
If you have loose-fill insulation that is gray, soft, and without a shine, it is probably cellulose insulation. Cellulose contains a high percentage of recycled paper and does not contain minerals. Cellulose looks like shredded gray paper, which looks different than asbestos insulation. Cellulose insulation is a perfectly safe type of insulation that is commonly blown into attics. It also comes in batt and blanket forms.
Loose-Fill Fiberglass
If you have loose-fill insulation that is white and fluffy and has a little shine, it is probably fiberglass fill. Because it is a glass product, fiberglass has a slight shine when subjected to bright light. It is very soft, almost like cotton candy, and is composed of very fine fibers.
Rock Wool Insulation
Often confused with asbestos-containing insulation, another mineral-based loose-fill insulation is rock wool. Rock wool has a fibrous, soft, cottony texture. Rock wool is usually gray, white, off-white, or brownish-white. It is a manufactured product, made by melting basaltic rock and dolomite with added binders. The raw material is heated to 2,750 degrees Fahrenheit until it melts, then the molten material is spun into fibers with air pressure. Rock wool is installed as loose insulation or as woven insulation batts.
What to Do With Asbestos Insulation Around the Home
If your loose-fill insulation fits the visual cues for vermiculite, the first thing to do is to avoid disturbing it. Asbestos fibers are most dangerous when they are airborne and can be breathed in. Leaving insulation undisturbed greatly reduces the risk of exposure. You can test the insulation for asbestos using an asbestos testing kit or by having a sample tested at an approved testing laboratory. If you discover that you do have insulation containing asbestos, you can leave it in place or have it removed by a local asbestos abatement company. For more information on dealing with vermiculite insulation, the U.S. Environmental Protection Agency (EPA) provides a wealth of information about identifying asbestos insulation, safety procedures, and how to remove it.
