Asbestos is a naturally occurring mineral that exists in abundance in numerous countries around the world. The material can be found in the soil or in exposed outcroppings of rock, and it exists in a variety of types, chemical compositions, and colors. Asbestos is a strong, virtually fireproof, and highly corrosion resistant material that has fascinated and served mankind for thousands of years, but in the late nineteenth century, its commercial use began to increase. In the late 1880s, several asbestos-containing composite products and materials began to enjoy popularity in the United States and around the world, and one of the most welcomed and widely utilized of these items was asbestos-cement.
Asbestos-cement is a mixture of primarily chrysotile or white asbestos and Portland cement. Because asbestos has a very high tensile strength and superior resistance to degradation from corrosive chemicals, it was considered to be an excellent additive to the particular chemical matrix of Portland cement. Depending on the specific use or application of the finished product, the ratio of asbestos to cement can vary from between 10 to seventy-five percent by weight. Once the cementitious product is fully cured, the asbestos fibers are bound in a hard mass that is stable and durable.
One of the earliest asbestos-cement products that had appeared in the United States went on the market in 1905, and it was in the form of a coating that had been developed by H. W. Johns Manufacturing Company (later to be known as Johns-Manville). The asbestos-cement coating had originally been promoted as a highly effective roof repair material that could add years of life to roofs that were once thought to be beyond repair. Often sold as a convenient, premixed paste, asbestos-cement soon became the low cost material of choice for roof and flashing repairs or waterproofing around chimneys, skylights, roof vents, drainage scuppers, etc.
Asbestos-Cement Would Soon be on the Rise
It was quickly discovered that asbestos-cement-based coatings could be successfully and cheaply used as a protective and insulating covering for high temperature steam pipes, hot-blast furnaces, boilers, and distillery vats. Because of its resistance to fire, asbestos-cement coatings were widely used to cover numerous structural elements of wood buildings, particularly in high hazard areas such as restaurant kitchens. The popularity of asbestos-cement rose sharply over a relatively short period of time, and soon H. W. Johns was joined by other large manufacturing companies of the era such as: Baltimore Roofing & Asbestos Manufacturing Company, Inc; Flintkote Company; Keasby and Mattison Company; Phillip Carey Manufacturing, and others.
The use of asbestos-cement took a step forward when, in 1907, the Austrian engineer Ludwig Hatschek patented a machine and accompanying processes that allowed for the manufacture of pre-formed asbestos-cement products. Hatchek’s machine involved the use of a series of wet rollers that facilitated the production of asbestos-cement flat sheet goods; additional developments by Hatschek led to the inexpensive and mass production of asbestos pipes and corrugated materials. The new asbestos-cement products would soon become widely embraced by a variety of industries due to the following desirable characteristics:
- High tensile strength
- Superior durability
- Impermeable to water
- Highly resistant to rot, corrosion, and soiling
- Fire and heat resistant
- Low maintenance
- Termite and other insect resistant
- Superior warp resistance
- Low thermal conductivity
- Superior electrical insulation qualities
- Low cost
Due to the many advantages of asbestos-cement, the material was soon on its way to extensive usage in the United States. Manufacturers wasted little time before incorporating the new wonder material into products such as wall shingles, roofing materials, flat millboard products, decorative moldings for ceilings and walls, pipes, floor tiles, acoustic tiles, electrical panels and conduits, environmental surfaces for laboratories, and much more.
The Insurance Industry Gives its Stamp of Approval to Asbestos-Cement Roofing materials
Prior to the advent of modern day fire fighting equipment and techniques, structural fires were a far greater threat than they are today. During the first half of the twentieth century, nearly all structures were wood frame, and in urban areas, these buildings were typically built in very close proximity to each other-a fire in one building could, and generally would, spread quickly to adjacent structures-the 1871 fire that virtually destroyed the entire city of Chicago being a prime example. Because of the nearly fireproof nature of asbestos-cement shingles, the insurance industry soon became a primary promoter of the use of the product for residential and commercial buildings in cities and towns across America.
Asbestos-cement products grew steadily in popularity as manufacturers offered residential builders and commercial contractors a wider and wider variety of flat sheet and corrugated goods that were made available in convenient sizes and thicknesses. Additionally, manufacturers soon began to stamp a variety of eye pleasing textures onto asbestos-cement sheet goods and shingle materials that eventually offered consumers myriad color choices as well. Asbestos-cement products offered builders superior ease of fastening that led to greater construction efficiencies, which, when combined with the relative low cost of the material itself, made asbestos-cement building materials hard to resist.
Soon, the material was everywhere. Asbestos-cement building products were widely used in the construction of large factories, retail outlets, military installations, entire residential subdivisions, government and educational structures, etc. Asbestos-cement products also found their way into offices and other locations when the material was used for partitioning, furniture, and numerous other products. By the early 1970s, at which time major health concerns about asbestos led to strict prohibitions against its use, asbestos-cement products were ubiquitous in the United States, as well as numerous other countries around the world.