Through the mid 1970s, asbestos was frequently used in the construction of private and commercial buildings and one common use for materials made of asbestos was in roofing shingles and tiles. Any home or other structure that was either built or remodeled before 1980 could very well have asbestos shingles on the roof. Asbestos roofing shingles are seen less frequently these days in newer buildings.
Roofs that had asbestos roofing shingles were often referred to as “asbestos roofs.” However most of these roofs had less than 30% asbestos in them and are actually classified as “asbestos-containing materials.” Transite was the most common kind of roofing tiles made of asbestos. They were made with cement, asbestos, and fiber and other materials mixed in. This mixture of cement and asbestos could easily be molded, cut, and drilled with holes. These roofing shingles were not just fire resistant but non-corrosive and durable. If these roofs are maintained well, they can last 100 years.
However, people who worked in facilities that made asbestos roofing shingles, installed shingles, cut roofing tiles, or worked in home repair on older roofs, are at much greater risk than the average person of developing mesothelioma, a rare and deadly form of cancer attributed to asbestos exposure. When intact, the shingles are generally not hazardous, but the process of manufacturing and installing the shingles often released deadly asbestos fibers into the air.