In 1977, the official state rock of California was found to cause cancer. Asbestos–a building product hailed through most of the 20th century as a “wonder fiber” was killing workers who breathed its microscopic dust in mines, asbestos plants and shipyards, decades after their exposure. When the Environmental Protection Agency (EPA) discovered this, they began restricting its use.

This natural mineral, drawn from serpentine rock, stands up to intense temperature. Prior to its toxic waste status, its outstanding resistance to heat, combined with its fibrous makeup and low cost, ushered it into the manufacture of thousands of products from toasters to ductwork for more than 60 years.

With the discoveries of asbestos hazards, an estimated 25 million American homes gained a new kind of poltergeist: an invisible menace that may or may not be floating in the air and that is–at the least–scary. Though the EPA restricted its use as a building material in the 1970s and proposed a 10-year phase-out of products containing asbestos in 1986, people living in homes and using products built earlier are understandably nervous.

In addition, lending institutions and real estate buyers are balking at properties that contain asbestos hazards. Joel McClain, Jr. of P.W. Stephens Residential, Inc., a California-based asbestos abatement service, points out, “It’s becoming a liability issue. If you expose future home buyers to a known hazard or sell a property without full disclosure, you’re setting yourself up for law suits.”

Homeowners I work with while inspecting their homes have lots of questions: Do small amounts of asbestos in your home really pose a health threat? How can you determine whether or not your home contains asbestos? If a home does contain asbestos, what should you do about it? What can you do about it? You may be surprised to find that asbestos is relatively easy to identify and–if it presents an immediate hazard–dealing with it can be a manageable task.

The Health Risks

To date, most research has centered around asbestos workers and their families, with whom it has been proven chronic breathing of asbestos fibers causes permanent scarring of the lungs (“asbestosis”), lung cancer and mesothelioma (a rare cancer of the intestinal tract and lungs). At present, however, no definitive research links disease to incidental exposure in the home.

This doesn’t necessarily mean there’s no risk. Data is difficult to gather in so broad a segment of the population, particularly because health problems may show up 30 to 40 years after exposure. A growing number of doctors and researchers are concerned about the long-term effects of low-level exposure. As a rule, asbestos fibers tend to attach themselves permanently to lung tissue; long-term, residual accumulation might catch up with you. The prudent assumption, voiced by Lee Thomas, former Administrator of the EPA , is that there is “no safe exposure” to airborne asbestos.

Must Asbestos Be Removed?

Not all asbestos is necessarily dangerous. Of the millions of homes that contain asbestos, only a fraction actually contain hazardous airborne asbestos fibers.

Keith Starner of Research Triangle Institute, a not-for-profit research organization presently studying the effects of asbestos, points out that the hazard of airborne asbestos fibers “depends to a great extent on the condition of the material, how often people go into the room where it’s located, and how much air moves through the space.”

It’s when asbestos is exposed and friable–flaking or crumbling–that it’s likely to become airborne. Both the EPA and the Consumer Product Safety Commission recommend leaving asbestos alone unless it’s friable.

Asbestos materials in good shape often can be “encapsulated” by an asbestos abatement contractor to add a layer of protection. This involves coating asbestos with a heat-resistant paint or sealant (approved by the EPA) that creates a protective barrier and converts surface fibers into a safer form. Be advised that encapsulating can be temporary and almost as expensive as removal, depending upon the project, and may make later removal more difficult.

To protect pipes or ducts that are sound from future damage, they can be enclosed in walls, or you can box around them. If asbestos is enclosed, the fibers usually aren’t released into the air and therefore it isn’t an immediate hazard.

Friable asbestos that is beyond repair or containment should be removed by a qualified asbestos abatement contractor. Hourly rates generally run from $200 to $400; estimates are usually quoted by the job.

Where to Look & What to Do

How do you know if you have asbestos in your home? Asbestos is often off-white; less-common types are blue or brown. Its appearance generally depends upon the material it was mixed with to make it workable: cement, polymers, starch, asphalt, or other binders.

Here’s where to look for asbestos and what to do if you find it:

Heating ductwork. Some ducts are made largely of asbestos; other metal ducts are wrapped with a cellulose-asbestos, air-cell insulation. Both look a bit like off-white corrugated cardboard; asbestos sheeting insulation has a similar appearance but without the corrugations. In addition, registers may have asbestos taping inside.

Ductwork made of asbestos is a major concern because when it begins to deteriorate, fibers are blown into the house. Talk with an asbestos abatement contractor about removal. Removing ductwork costs from $12 to $25 per lineal foot–from $1000 to $2000 in a standard basement. Replacement is additional.

Wrapped ducts should be removed if wrapping is friable. A stop-gap measure for duct wrapping that’s sound is to have it encapsulated.

The furnace may have an asbestos lining at the base or sit on an asbestos pad. A special asbestos cloth may join furnace or boiler to ductwork. If any of these are exposed to damage, they should be encapsulated or removed.

Plumbing. Some pipes, particularly those connected to radiators or steam heat, are often jacketed with asbestos. Asbestos pipe wrap, often covered with canvas, has a crumbly white surface. If pipe wrap has small holes, it’s generally better to repair it than remove it. You can caulk holes, then wrap with rewettable glass cloth. Don’t use duct tape–it will fall off with time.

Wiring. Be wary of old knob-and-tube wires that have a white coating covered with black fabric. If you’re remodeling, avoid pulling out these old wires; bypass with new wiring.

Fireplace. Artificial logs or ashes manufactured prior to 1978 probably contain flaking asbestos. The ashes are a serious concern; remove them immediately. The logs don’t release fibers unless friable.

Wood stove. Wood-stove gaskets and protective panels for wood stoves or ovens may look like grayish-white stone. If exposed to damage, remove and replace with acceptable material.

Crawl space or basement floor. Remember that fibers may have collected on the ground or floor beneath ductwork or piping. Have this area cleaned by a trained asbestos abatement professional or–if you must–wet mop to clean up. Never sweep or vacuum asbestos fibers–they are about one-thousandth the thickness of a human hair and will go right through a household vacuum and into the air.

Walls and ceilings. Sprayed acoustical “cottage cheese” ceilings generally have a very low percentage of asbestos, though some may contain as much as 40 percent. Avoid doing anything that will loosen the material (for example, don’t sweep the ceiling). Removal can be quite expensive (from $5 to $30 per square foot).

Most patching plaster and drywall joint compounds–until 1979–contained a small amount of asbestos. Avoid scraping and sanding them.

Some plaster walls in older homes contain blown-in insulation that includes asbestos; it looks like hard cotton. Only have this removed if you’re remodeling.

Flooring. Even recently-manufactured vinyl floor tiles contain a modest amount of asbestos. Because it is ingrained in the material, it doesn’t pose a threat. The tile and its felt backing only become a problem when you’re renovating. Don’t sand or scrape these materials. Rather than remove old vinyl flooring, the best recommendation is to cover it with underlayment, then add your new floor.

Roofing and siding. Some older shingles are made from asbestos mixed with cement or asphalt. Asphalt-asbestos shingles don’t release fibers easily; asbestos-cement shingles can, so be careful during a remodel. Avoid breaking or crumbling either kind. Roofing tars and felts also contain asbestos but, again, are unlikely to release fibers unless heavily damaged.

Getting Help

Qualified asbestos abatement inspectors or some plumbing and heating contractors can help locate suspect materials. A lab test of a sample from the material–generally under $50–can give you a definitive answer as to whether or not the sample contains asbestos.

The EPA has a toll-free number you can call for laboratories who will do this work, including instructions for obtaining and packaging the sample. (See below.)

Though some states require licensing of asbestos abatement contractors, some don’t. Unscrupulous contractors might sell you a bill of goods you don’t need or do a shoddy job. A fly-by-night contractor may leave airborne asbestos levels that measure 3 to 4 times higher than before the job. If this happens, clean up costs can be astronomical.

You can also contact your regional office of the EPA for information. Determine the level of training your contractor has had and request references. If your state has a licensing program, be sure your contractor is certified. If no certification program exists, get proof that workers have been trained in an EPA-approved program.

Be sure to get several estimates and be wary of any that are exceptionally low or high.


Bob Beisbier, owner of BK Home Inspections, is a Certified Master Home Inspector who has been providing professional and thorough home inspections in southeast Wisconsin for over 12 years. Bob is Infrared certified, DILHR Certified, and provides Home Energy Tune-ups, Environmental Data Reports, Pre-sale Home Inspections and Pre-offer Home Inspections.