Black Mastic and Asbestos Adhesive Removal
If you pulled up old vinyl tile or sheet flooring and found a black, tar like glue underneath, you may be looking at black mastic. This adhesive was standard for gluing tile and linoleum to subfloors from the 1920s through the early 1980s, and a large share of it contains asbestos.
At Raleigh Asbestos Removal Pros, we test and remove this material for homeowners who don’t want to guess what’s under their feet.
What Black Mastic Actually Is
Black mastic, sometimes called cutback adhesive, typically holds 15 to 25 percent asbestos by weight. Manufacturers added the fiber because it made the glue tougher and more heat resistant.
Armstrong, Congoleum, and Kentile Floors were among the larger flooring companies that sold products using this adhesive during the mid twentieth century, and their tile and mastic combinations still turn up in Triangle area homes during renovations.
The only way to know for certain whether your mastic contains asbestos is lab testing. Color and age are clues, not proof.
Why This Shows Up So Often in Local Homes
Census data compiled by NeighborhoodScout puts roughly 15 percent of Raleigh’s housing stock at pre 1970 construction, with a sizable share more built through the 1970s. That decade matters because mastic manufacturers kept asbestos in their formulas into the early 1980s.
A home doesn’t need to look old to have this material. Additions, remodeled kitchens, and finished basements from that era can all hide it under newer flooring.
| Build Era | Asbestos Mastic Likelihood |
|---|---|
| Before 1970 | High |
| 1970 to 1980 | Moderate to high |
| 1981 to 1990 | Low, testing still recommended |
| After 1990 | Very low |
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What North Carolina Requires
North Carolina adopted the EPA’s NESHAP threshold, so any project disturbing more than 260 square feet of asbestos containing material has to be reported to the NC Department of Environmental Quality before work starts. Abatement contractors also need a license through the NC Licensing Board of General Contractors, and every worker on the crew must hold a current accreditation through NC DHHS.
A homeowner scraping mastic on a small patch themselves is technically allowed, but the health risk doesn’t shrink just because the square footage does.
How We Handle Removal
- Collect a sample and send it to an accredited lab before any disturbance begins
- Seal off the work area and run negative air pressure to keep fibers contained
- Keep the material wet throughout removal, since dry scraping or sanding is what actually releases fibers into the air
- Bag and dispose of the waste at an approved facility, with documentation you can keep for your records
- Test the air once the job is done, before we call it finished
Intact mastic that stays covered under new flooring usually isn’t dangerous. It becomes a problem when someone sands it, dry scrapes it, or runs a heat gun over it during a DIY flooring project. If you’re planning a renovation and see that black adhesive under your old tile, get it tested before you touch it. We handle sampling and full removal for homes across the Raleigh area.