What Are Asbestos Shingles?

Asbestos shingles are a type of construction material used to form the exterior sheathing of a roof. They are very similar to today's fiber cement shingles, but contain some quantity of asbestos fibers in additional to the traditional cement board elements. This material was used throughout much of the 20th century to construct roofs on homes and small commercial buildings. Since the 1970s, production of asbestos-containing products has been discontinued due to health concerns related to asbestos fibers.

History of Asbestos Shingles

• Asbestos was first used by builders in Europe in the 1800s, who added it to to siding, tiles, shingles, and a variety of other products. Once users began to recognize the benefits of this material, its use quickly spread to the US. Asbestos shingles quickly began to replace other materials like slate and clay, which were more expensive and less durable. From the early 20th century through the 1970s, asbestos shingles remained one of the most dominant roofing materials available. While asbestos use was wide-spread, many also feared it was a health hazard, with deaths attributed to asbestos-exposure dating back to the 1920s. By the late 1970s, the dangers associated with asbestos could no longer be ignored. The EPA issued warnings regarding its use, and the resulting public fear effectively ended this product's production by the 1980s. Currently, there are no US companies that still produce shingles containing asbestos.

Properties of Asbestos Shingles

• Throughout history, asbestos has been considered somewhat of a miracle product. It is as strong and durable as marble, yet is made up of fine threads that take up very little space. By adding it to shingles, manufacturers were able to increase their strength, making them more resistant to damage or extreme weather conditions. In addition, the asbestos fibers made the shingles virtually fire-proof, which was a critical factor in the early 20th century. Asbestos shingles also acted as thermal insulators and helped to keep outside noises from entering the home. It is important to note that these shingles were not made from asbestos alone, but were instead comprised mainly of cement. The term "asbestos shingles" means only that some amount of asbestos can be found in the material, with percentages usually ranging from 5 to 35 percent.

Asbestos Dangers

• According to the US Environmental Protection Agency (EPA), there is a definitive link between asbestos exposure and lung disease. When one breathes an asbestos fiber, it can become trapped in the lungs. As the body tries to rid itself of the fiber, it can begin to cause damage to itself in the form of breathing difficulties, lung cancer, heart failure, or mesothelioma. Because of these dangers, asbestos use in the building industry was prohibited in the US as of 1990. Existing asbestos shingles and other materials are permitted to stay in place, but new products are banned from production or installation.

Asbestos Shingles in the Home

• Many homes built before the 1980s may have asbestos shingles, as well as asbestos-containing roof felt and adhesive. As long as the roof is intact and the shingles are not disturbed, there is virtually no danger of health effects from asbestos exposure. Danger occurs only when the fibers are breathed in, so as long as the asbestos is encased in the cement mixture of the shingles, the fibers will not be airborne. If shingles become damaged in any way, the asbestos fibers may be released, posing a health hazard. In this case, the asbestos shingles should be removed or encapsulated by a trained and licensed professional. Attempting to remove asbestos shingles on your own can have catastrophic consequences. By the same token, one should take care to never drill into these shingles, or to disturb the surface using a power washer or any other tool.

Removal and Disposal

• If asbestos shingles are found to be damaged or disturbed, they should be examined by a licensed abatement contractor. For small repairs, they may be able to remove and replace the damaged shingles, or seal them with a protective coating that will contain the asbestos. If this is not possible, the contractor will have to remove the shingles entirely, and replace them with a safer material. They will first obtain permits from local authorities, then safely remove the shingles to minimize exposure to the home's occupants and the public. Generally the roof will be encapsulated with a protective tent, and a HEPA filter will be used to keep fibers from escaping. All roof materials will be kept wet so that asbestos fibers will not float away. The shingles will then be discarded safely at a landfill or recycling plant. Per OSHA Standard 29 CFR 1926.1 101, all asbestos removal must be performed by trained individuals working for licensed companies.