Working in historic or older homes can bring another layer of safety considerations. One of these potential hazards is coming across cutback adhesives, which were used for the installation of products such as vinyl composition tile from approximately 1880 to 1980. Another example of how these products historically were used includes the construction of and sealing walls on Navy ships. Cutback adhesives were asphalt-based and black in color, and could contain asbestos, as could vinyl and sheet good products.
“Any vinyl, vinyl composition tile, or linoleum that is 6″ x 6″, 9″ x 9″, or 12″ x 12″, or in sheet goods that were installed before the late 1980s, should be looked at carefully,” recommends Sam Biondo, MAPEI’s National Technical Presenter.
The National Institutes of Health (NIH) defines asbestos as “six minerals that occur naturally in the environment as bundles of fibers that can be separated into thin, durable threads for use in commercial and industrial applications.” These fibers were used to strengthen asphalt-based adhesives. The NIH lists possible health risks associated with asbestos exposure as cancers including mesothelioma, asbestosis, and other nonmalignant lung and pleural disorders.
The U.S. Environmental Protection Agency (EPA) banned new uses of asbestos in 1989. However, according to The Mesothelioma Center, adhesives containing asbestos materials are still in millions of old structures, where they can become hazardous if disrupted. There are several factors noted by the NIH that can impact whether someone is affected by exposure to asbestos, including how much exposure, length of exposure, and source of exposure.
If an installer comes in contact with cutback adhesives on the job, Biondo offers this advice.
“When in doubt, have it checked. There are kits available online or at your local hardware stores that you can get and conduct a test before you disturb the floor, or you can call in a pro,” says Biondo.
Jeff Johnson, MAPEI’s Business Manager for Floor Covering Installation Systems, recommends using a professional in removal situations.
“Asphalt-based cutback adhesives can be removed over concrete substrates readily using mechanical means like razor scraping or shot blasting, but should be done only by a certified asbestos removal agency unless you know for certain that there is no asbestos involved,” notes Johnson. “Removing asphalt-based cutback adhesives from old, existing wood flooring will be a lot more difficult because of the tenacious bond of the asphalt to the wood. In many situations, it might be recommended to NOT remove the asphalt, but encapsulate it using a polymer-modified cement and/or covering it with another layer of ¾” plywood prior to installing the next floor.”
Following these procedures will raise the overall elevation of the floor covering. It is important to take these elevation gains into account with doors, cabinets, appliances, and plumbing fixtures. Johnson cautions that although there are many great options for encapsulating the asbestos cutback adhesives, it is equally as important to make the homeowner aware that the cutback always will be there, and sooner or later, it may need to be removed.
“Asphalt cutback adhesives are becoming rarer in today’s installation adhesive portfolio because of their inherent issues of discoloration and not being terribly environmentally friendly,” he explains. “I would always urge caution when dealing with any black adhesive residue on the subfloor due to the use of asbestos as a fiber reinforcement even up until the late 1980s. Usually, when I see old black adhesive residue, the first thing to do is test it for asbestos.”
The Occupational Safety and Health Administration (OSHA) has regulations regarding asbestos exposure on the job. To learn more about the hazards of asbestos and OSHA standards, visit osha.gov/asbestos.