What is Asbestos Siding and Can it Be Covered?

What You Need to Know About Asbestos Siding

Before Asbestos was banned in the 1980s by the EPA, it was used in some construction materials for its benefits. It was banned once adverse health effects were discovered from accidentally inhaling the fibers—increasing the risk of lung-damaging illnesses and/or cancer.

However, since many homes and buildings had it built into their structures, it can take years to discover.

Many homeowners or property owners might discover it after storm damage, renovations or from learning a building’s original materials. In any case, asbestos exposure remains a threat—even in siding.

What is Asbestos Siding?

Asbestos was mixed into cement to form structures that were fire and chemical-resistant, especially for materials such as insulation, vinyl floor tiles, asbestos shingles and asbestos cement siding.

Asbestos siding is a siding shingle made from a mixture of Portland cement mixed with asbestos fibers. It’s very brittle and can crack when disturbed, such as nailing into it or sanding it. When the asbestos is broken up, that’s when the fibers enter the atmosphere (and sometimes water), proving to be hazardous to your health.

Yet, it typically does not pose a health risk if left alone with no damage. However, there is always a chance it can degrade and begin causing you issues.

History of Asbestos Siding

After the development of asbestos cement in 1905 by the Johns-Manville company, asbestos siding became popular by 1910—under the trademarked name, Asbestoside. Homes and buildings were fitted with asbestos siding and other products well up until the 1970s before the EPA ban.

Types of Asbestos Siding

While asbestos is dangerous all around, it encompasses multiple types with some being more common in siding and shingles than others. According to Architectural Digest, here are the types of asbestos that can be found in house siding:

  • Actinolite: Actinolite is featured in sealants, paints, and asbestos insulation and can also be mixed with cement. It’s normally white or gray but can also be yellow or green.
  • Amosite: This common siding material is brown, gold, or black, and it usually has a coarse texture.
  • Chrysotile: The most common type of asbestos used in siding materials, chrysotile is grayish-white and brittle to the touch.
  • Crocidolite: Crocidolite isn’t popular in even original siding since it’s more expensive than other asbestos types. It has a blue tone and a silky texture.
  • Tremolite: Common for use in fabric construction materials and in the creation of roofing and plumbing parts, tremolite can be either white or dark green.

However, since asbestos fibers are microscopic, understanding which type of asbestos is in your siding can be difficult without a professional lab to test it. This makes identifying the siding itself even more crucial as you can’t fully rely on seeing any of the microscopic identifiers.

How to Identify Asbestos Siding

Whether you’ve had your asbestos siding fall apart and become a health hazard, or you’re being proactive and addressing your siding early on, knowing what to look for is the first step.

It’s a difficult and potentially dangerous task for homeowners or property owners, but can still be done. Yet, the best way is to have an asbestos-removal professional take a look and confirm the presence of asbestos through testing with a quality lab.


Asbestos fibers are tiny and hard to identify visually without a microscope. But if you see a wavy pattern on the bottom edge of the siding material, this may be a sign of asbestos. Another way to figure out if your siding shingles contain asbestos is to find the manufacturing code on the back of the shingles—helping you discover the age and origin of the siding.

Home or Building Age

Since asbestos was common until the 1980s, homes built before then are usually prime candidates for asbestos-related materials or exposures. Knowing when your home or building was constructed can be the first clue for further investigation.

Professional Inspection and Testing

Even if you are able to visually identify what may be asbestos siding shingles, the only real way to know is to hire an asbestos inspection professional to take a look. They will then test the siding by taking a sample—often sending to asbestos testing labs for confirmation.

How to Deal with Asbestos Siding

Since asbestos fibers becoming airborne is the biggest concern, deciding what to do with your asbestos siding can be challenging. When choosing a strategy, it’s best to minimize as much risk as possible—whether that’s short-term or long-term.

Covering Asbestos Siding

Yes, you can cover asbestos! If your asbestos siding is already undisturbed, then you can cover it to keep it from breaking down and turning into a health hazard.

This is usually the preferred method for dealing with asbestos siding and many siding companies are well-experienced in techniques for covering over existing asbestos-cement siding with new vinyl, aluminum, or fiber-cement siding.

However, if you’re asbestos siding is already breaking down and causing issues, or you want to be safe, removal is the next best option.

Removing Asbestos Siding

Asbestos siding removal is dangerous due to the health risks. And while some areas allow homeowners to remove it themselves, it’s best to have an asbestos professional remove the siding. If you go this route, it may take some extra effort and resources, but you’ll know that your home or building’s siding is asbestos-free going forward.

Uncover Siding Issues by Testing for Asbestos

Homeowners and property owners alike will likely be dealing with asbestos-related building materials from the past for years to come—especially in siding. But even if you suspect asbestos siding, not much can be done without proper testing to confirm its presence.

Once a sample has been collected and sent off to an asbestos testing lab facility that tests for asbestos. Lab professionals will be able to confirm or deny the existence of asbestos, which gives you the information you need to make an educated decision for your home or building.

Environmental Hazards Services provides quality asbestos testing that can help you identify the substance and prevent any related health effects.

Contact us today and set up testing for projects of any size, scope or complexity.