Q&A about how to recognize potentially hazardous roof or floor adhesive, mastic, or sealant that may contain asbestos.

This article series provides dates of manufacture of asbestos-containing adhesives, mastics, sealants, and includes photographs and text describing the appearance of such products. Page top photo of black mastic floor tile adhesive provided courtesy of reader G.M.

Asbestos-Containing Floor Adhesive / Mastic Identification & Age

These questions & answers about recognizing floor tile adhesive or floor tile mastic that contains asbestos were posted originally

at ASBESTOS MASTIC IDENTIFICATION - be sure to read that guidance too.

Asbestos is safe and legal to remain in homes or public buildings as long as the asbestos materials are in good condition and the asbestos can not be released into the air.

Generally the safest approach is to leave such flooring alone and to cover it over with a coating or with another layer of flooring.

See ASBESTOS FLOORING HAZARD REDUCTION

And also if you need to remove the floor, see ASBESTOS FLOORING REMOVAL GUIDE

IF you are faced with a requirement for demolition and if you are uncertain about the flooring's asbestos content and cannot identify it through our guides, then you have a sample tested.

See ASBESTOS TESTING LAB LIST

On 2019-07-14 by (mod) - asbestos release unlikely from old mastic adhesive now covered over

I agree that unlike friable materials, asphalt-based (black) mastic is not particularly friable .

If an asbestos containing floor is covered it is not normally going to be an airborne asbestos dust concern. You'd have to have an air path from the postulated grit and dust into the building air space as well as measurable air movement.

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On 2019-07-14 by Anon

Thanks for the feedback. I’m pretty much of a neat freak so house has been cleaned many many times since flooring install. Would you expect that any asbestos would get airborne in the future from what I described? Thanks

On 2019-07-14 by (mod) - asbestos release from covered-over flooring?

Flooring mastic or adhesives from the 1970s could contain asbestos. At this point with the work completed what remains is to inspect and if necessary perform additional dust cleaning in your home. If you're concerned about asbestos dust contamination used a tape of sample procedure that you can find at this website to have a sample of Representative dust tested.

On 2019-07-14 by Anonymous

Forgive me for the ignorance of this question but I’ve learned a lot since a basement flooring install that was done a while ago. Had contractor redo the cosmetic parts of the basement. The old (70’s) carpet was pulled up.

Very coincidentally, I was talking to my neighbor and he alerted me that flooring adhesives from that timeframe could have asbestos in them. The adhesive looked to be black and similar to pics online of mastic. I asked contractor about it and he dismisses the idea.

I asked if he could put something over the mastic anyway to encapsulate it. He put a masonry waterproofing paint over it. The product used was UGL latex masonry Waterproofer.

New vinyl plank flooring was installed directly over that (no vapor barrier). I later learned that this waterproofing product is not intended for use on floors and, by chance, contains a very high content of basically sand and grit and product is said to have a “sandy feel” to it. In retrospect, I would have done this differently of course. I called an environmental company and an asbestos inspector came out for inspection.

I had said my concern was about walking on new floor causing abrading/compromising of the mastic below (especially with the gritty Waterproofer used on top of mastic).

After we talked for a while about the situation, he said that even if the mastic was, by chance containing asbestos, the asbestos in the mastic is so bound in that “matrix”, that airborne asbestos from the mastic was not believed to be possible from what I had described.

A sample of the mastic was not taken based on that assessment. That was good to hear but I still feel uneasy. I was curious to hear what you thought about this. Thanks

On 2019-07-13 by (mod) - mastic can be up to 85% asbestos.

Thanks for an interesting question, Anon.

I've commented on this before - what you look for is what you find - in forensics. So if a lab is ONLY looking for large asbestos fibers they will not see the fines, asbestos "waste" or dust that was used as filler in some floor tiles and in some mastics to add body.

Therefore I'm not surprised that someone whose procedure looks for both fibers and the filler forms of asbestos would find higher percentages of asbestos in the material.

A second variable is exactly what portion of the mastic was selected for analysis - it may not be consistent.

So yeah, 85% asbestos in asphalt-based flooring adhesive or mastic sounds a bit high but not impossible.

On 2019-07-13 by Anonymous

I’ve seen some info online that says that mastic can be up to 85% asbestos. Whether that is fibers or asbestos waste of some sort, doesn’t that sound high?

On 2019-07-02 by Anonymous

Thanks for your feedback- I would definitely be interested in any additional info you could come up with.

On 2019-07-02 by (mod) -

Interesting question, Steve.

I've seen that range of level of asbestos in nzstics as nd in flooring too, and will need to do more research to offer an authoritative answer. I think the problem isn't so much actual variation in asbestos as in methodology.

Many products used asbestos in both fiber form and also in form of asbestos waste: shorts and fine particles as filler, oncluding on adhesive masticd. Some lab methods look only for fibers.
If you're not looking for a material in other forms you won't see it and won't report it.

Also some Labs report their asbestos findings as particles and others by weight and others by volume. So people may be mixing up types of measurements.

On 2019-07-02 by Steve

I have found a huge range online regarding the percentage of asbestos content in black mastic. What would a realistic range of asbestos content percentage be for black mastic used in the mid 1970’s? In New England ( not sure if that is important) thanks.

On 2019-03-25 by (mod) -

Tamra

Don't freak out - doing so is itself bad for your health.

If your removal was using wet or damp methods you've taken a key step to minimizing a dust hazard.

IN the ARTICLE INDEX you'll see more articles on how to remove asbestos flooring and mastic while minimizing the risks involved.

If you are still panicky then collect a representative sample of settled dust have that screened by an asbestos test lab. The same index gives articles on how to do that and lists certified asbestos test labs.

On 2019-03-25 by Tamara McMakin

Hi. My house was,built in 1960. We are renovating our family room. Decided to scrape up tile floor. 2 layers and under 1st layer is the black adhesive that i read contains,asbestos. Freaking outbecause we,scraped up a bunch already and had room tarped off but not well enough. Wondering how far the dust travels because my daughter was,home upstairs and freaking out that she breathed any in. Please help!

On 2018-09-03 by (mod) -

Possibly yes

On 2018-09-03 by Anonymous

Does this look like it would contain asbestos

On 2018-07-11 by (mod) -

JM

You raise an interesting point since cork flooring itself is not an asbestos product but black mastic adhesive used to install it could contain asbestos fibres and filler.

For rooms that have had flooring removed, I would damp wipe up all dust and debris and then add new finish flooring over top. Mastic is not particularly friable unless you're doing something aggressive like sanding.

Where I have had to remove old mastic I've used solvents, starting by trying simple water. Water won't work on asphaltic mastic but does work on some other latex based adhesives.

For rooms where carpet is down I doubt there'd be much worry. I already described the mastic stability. Intact floor adhesive is not like a radioactive substance and cannot emit harmful asbestos particles that pass through other floor coverings.

On 2018-07-11 by JM

We have an 1961 house that had cork (actual cork) that was removed after we purchased the house. The cork was scraped off and it had a darker glue. This was done before we got into the house or had the AC running.

See picture. There are 3 bedrooms like this that have carpet over it. I am working on scheduling a test for possible asbestos in the mastic. In the meantime, we are debating if we need to remove the carpet, seal it or some other layer and the put down new flooring. Does this darker glue look like possible asbestos? Any recommendations for those rooms that now have carpet?

On 2018-06-14 by (mod) -

Yes possibly. It's probably safer and (if you're not testing) less expensive to treat the floor as presumed to contain asbestos.

On 2018-06-13 by Brandy

Do you think this could contain asbestos? House was built in 1979, and this flooring, a sheet linoleum was probably added years later when the porch was enclosed. It has white paper backing and is very think and brittle and is very dusty.
My husband is removing it right now, and I am very nervous!

On 2018-04-29 15:05:26.214683 by (mod) -

Latex-based adhesive, sometimes with asbestos, depending on the age of manufacture.

On 2018-04-29 04:16:04.791101 by Anonymous

@Anonymous,
I should add, if any was used at all...

On 2018-04-29 04:15:25.830598 by Anonymous

What type of asbestos was commonly used in brown glue pods?

On 2017-10-10 20:59:07.616691 by (mod) -

Smart question, Roger, but I think the answer is no. At least not usually. Some roofing mastics contained large amounts of long fibres that can show up as the mastic wears but floor tile adhesive mastic that contains asbestos will include smaller fragments you'd haver trouble seeing without a microscope.

So the absence of evidence would not constitute evidence of absence of asbestos.

On 2017-10-09 08:42:04.975436 by Roger

If the mastic is wearing off the floor from traffic would you be able to see the fibers

...

Continue reading  at ASBESTOS MASTIC IDENTIFICATION - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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