But homes built before asbestos was banned, and especially ones from the 1920s through the mid-1970s, may still have asbestos-containing materials in place. Because asbestos is inert, moisture does not decompose it over time like organic materials, and 60-year-old asbestos-cement siding—as shown in the photo at the top of the page—is often still in excellent condition. Asbestos was also used in roofing, insulation, coatings, flooring and ceiling tiles.

    The good news is that asbestos is only dangerous when the tiny fibers are “friable,” which means loose and able to float in the air. The general recommendation of the U.S. Environmental Protection Agency (EPA) is to leave asbestos-containing building materials alone unless the they are damaged, frayed, or otherwise deteriorating. Don’t disturb them. Sawing, drilling, sanding, or removal will release the dangerous friable particles into the air.

   There are no standard visual clues that a product contains asbestos. It can only be positively identified in a lab, using a polarized-light microscope—unless you get lucky and find an asbestos label or imprint on the material. But there are a number of mid-20th century and earlier building products that are known to contain asbestos and fairly easy to recognize. Here are five of the most common:

  1. 1)Asbestos-cement siding - The most popular style has a wavy bottom edge and striated surface. We still see it often in the older sections of town, since the stuff is nearly indestructible. See our blog post “The home has asbestos siding. What should I do?” for more information on this product.

  2. 2)Asbestos in floor tile - If you are a baby-boomer, you will recognize the streaked or multi-color spotted tiles from the floor of your elementary school classroom. Mid-century sheet vinyl flooring also contained asbestos. Asbestos was added to vinyl, rubber, linoleum and asphalt floor tile compositions. Beware: you might find older tile with asbestos content under a layer of newer tile during remodeling work.

  3. 3)Asbestos-cement and asbestos-asphalt roofing - There was an asbestos cement corrugated roof panel used primarily for industrial buildings and rarely encountered anymore, but we still occasionally see asbestos-asphalt and asbestos-cement shingles that are 60+ years old still in place. It is usually a thick shingle and often in a scalloped pattern. Most homeowner’s insurance companies will not insure a roof that old and removal is hazardous, requires a professional abatement contractor, and is expensive. See our blog post “What is the life expectancy of an asbestos cement shingle roof?” to learn more.

  4. 4)Pipe insulation - Asbestos was used for pipe insulation as a wrap of woven cloth, a batt-like blanket, and as part of an applied coating. We recently came across some asbestos insulation in the crawl space of a 1920s house as a wrap for long-abandoned boiler piping. It was a fabric wrap similar to the close-up photo of the material at right, and much of it had been pulled down onto the ground by animals looking for nesting material. An arrow points to the pipe and insulation.
    Rock wool insulation is often confused for asbestos, but it is a completely different rock composition and not carcinogenic. To learn more, see our blog post “There’s old insulation in the attic marked ‘rock wool.‘ Is it really dangerous asbestos?”
  5. 5)Acoustic ceiling tiles and vermiculite attic insulation - Both of these may contain some asbestos, particularly acoustic tiles that predate suspended ceilings and were stapled into place

    Determining whether an older home has asbestos-containing materials is beyond the scope of a home inspection and most home inspectors, including us, disclaim responsibility for identifying it. The most obvious examples, like the ones noted above, may be called out for further evaluation when observed.

    But there are specialized asbestos inspectors who have the knowledge and experience to recognize an array of materials that are likely to contain asbestos and will also provide lab testing on samples taken. Sampling itself can release asbestos fibers into the air and the pros use a safety protocol that includes wetting the material to be sampled before removal.

   The EPA recommends the following guidelines for home asbestos safety:

                 Asbestos Do's and Don'ts for the Homeowner

  1. BulletDo leave undamaged asbestos-containing materials alone.

  2. BulletDo keep activities to a minimum in any areas having damaged material that may contain asbestos, including limiting children's access to any materials that may contain asbestos.

  3. BulletDo take every precaution to avoid damaging asbestos-containing material.

  4. BulletDo have removal and major repair done by people trained and qualified in handling asbestos. It is highly recommended that sampling and minor repair also be done by a trained and accredited asbestos professional.

  5. BulletDon't dust, sweep, or vacuum debris that may contain asbestos.

  6. BulletDon't saw, sand, scrape, or drill holes in asbestos-containing materials.

  7. BulletDon't use abrasive pads or brushes on power strippers to strip wax from asbestos flooring. Never use a power stripper on flooring that may contain asbestos.

  8. BulletDon't sand or try to level asbestos flooring or its backing. When asbestos flooring needs replacing install new floor covering over it, if possible.

  9. BulletDon't track material that could contain asbestos through the house. If you cannot avoid walking through the area, have it cleaned with a wet mop. If the material is from a damaged area or if a large area must be cleaned, call an asbestos professional.

While we hope you find this series of articles about home inspection helpful, they should not be considered an alternative to an actual home inspection by a local inspector. Also, construction standards vary in different parts of the country and it is possible that important issues related to your area may not be covered here.
© McGarry and Madsen Inspection


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