Asbestos Roofing Materials

Roofing materials that contain asbestos have been used in a wide variety of homes and commercial buildings since the early 1900s.

Two common roofing materials that often contained asbestos include:

• Roofing shingles
• Roofing felt

While the use of asbestos in roofing materials was phased out during the 1980s, many homes, commercial buildings and schools still have roofs made of materials that contain the substance. For this reason, any individuals seeking to make renovations or changes to an older roof should consult a professional first in order to test for the presence of asbestos.

Roofing Shingles

Asbestos roof shingles were widely used during the 1900s. Asbestos roof shingles typically contain a mixture of asbestos fibers, cement and other additives. The most common form of asbestos roof shingles, known as transite shingles, were composed of asbestos fiber and Portland cement.

This combination provided protection against problems commonly experienced with wooden roof shingles, such as warping, rotting and insect damage. In addition to these properties, asbestos was also an appealing material for roof shingles because it is fire-resistant, lightweight, durable and inexpensive to manufacture.

While roofs made with asbestos roof shingles are sometimes referred to as "asbestos roofs," they typically are comprised of less than 30 percent of asbestos.

Roofing Felt

Roofing felt is a building material composed of heavy paper that has been filled with asphalt. The material is supplied in rolls and is typically delivered in 15-pound increments, although additional weight increments may also be used.

Asbestos was frequently used as a component of roofing felt, as it added fire-resistance, elasticity and strength to the material. Most asbestos roofing felt was made of approximately 10 to 15 percent of the substance.

Roofing felt commonly contained chrysotile (white) asbestos, which was typically mined in California, Montana and Quebec. The felt was most commonly used in flat roofs on large commercial buildings but was also occasionally used in pitched roofs and in homes.

Hazards of Roofing Materials

Roofing materials that contain asbestos and are in good condition generally do not pose serious health risks. However, when asbestos roofing materials have become damaged or deteriorated, they can release harmful asbestos fibers into the air. These microscopic fibers can place individuals in the surrounding area at risk of asbestos exposure and asbestos-related diseases.

Once asbestos fibers have been released into the air, they can also become attached to the clothing of workers or other nearby individuals. These fibers can then be carried into the home, where additional individuals can be exposed.

Roofing Materials and Mesothelioma

When asbestos roofing materials have been disturbed and asbestos fibers have been released into the air, they can be unknowingly inhaled or ingested by individuals in the surrounding area.

Once inside the body, asbestos fibers cannot be broken down. Instead, they can become lodged in tissues surrounding the lungs and the gastrointestinal tract. Over time, the presence of asbestos fibers in these areas can lead to the development of inflammation and, in some cases, the development of a rare cancer known as mesothelioma.

Individuals Affected by Asbestos Roofing Materials

Roofing materials have commonly placed the following workers at high risk of asbestos exposure:

• Roofing contractors
• Maintenance workers
• Demolition workers

The materials have also placed other individuals at risk of asbestos exposure. These individuals include:

• Homeowners
• Hardware store employees

Other individuals not listed above may also have been placed at risk of asbestos exposure by contaminated roofing materials.