Masonry in Chimney Hole/Thimble - Asbestos Possibility?

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throughthethicket

New Member
Dec 14, 2025
2
Massachusetts, USA
Hi all. I'm having issues with chimney contractors and wanted to get people's take. I'm changing from a freestanding gas stove to a woodstove.

Had an inspection by two guys from the company. We need to demo the masonry in the hole to the chimney to make a 6 inch liner (code) fit, as it was originally a smaller gas liner. They signed off the inspection report and got things going.

Two DIFFERENT guys from the same company came by to complete the job. They took one look at this masonry and said they could not proceed as the masonry is asbestos. He was very certain and said he could "see the fibers" (which I did not think was possible). The house was built in 1964, but the town's GIS records that a flue and woodstove was installed in 1994; and this is the only chimney/stove in the house. When I showed him this record, he dismissed it saying that it could have only been work to build the chimney, and he is certain the masonry is asbestos.

The company, at least, is recognizing they messed up somewhere and is apologetic. I'm waiting to hear back next steps but am somewhat concerned that they're going to make me pay for an asbestos specialist for no reason. I'm personally testing the masonry for asbestos myself, but I can see them dismissing my test.

Any thoughts? Has anyone seen masonry like this that's asbestos before?

[Hearth.com] Masonry in Chimney Hole/Thimble - Asbestos Possibility?
[Hearth.com] Masonry in Chimney Hole/Thimble - Asbestos Possibility?
 
Asbestos in cement was phased out in the US in the 1970s and world in the 1980s but it is possible that someone had old stock being used up. Unlikely, but it's good to test for it. Another possibility is that this is fiber-reinforced cement, using fiberglass fibers. If so, wearing a good face mask should suffice.
 
Id take it in stride. They want to do the job, but want to keep everyone safe. This includes you and your family. I’d recommend testing it.
 
Test it and see. If it tests negative, and the chimney contractors still want a specialist, you can always rip it out yourself if your able.
You'll save some on the quote too.

Just a thought.
 
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From the pic you provided, I would be highly suspicious of asbestos. The company you hired wants to do the job, but paused work twice, they generally are way more experienced than homeowners in their line of work. Seems like they are doing the right thing by halting work, at least until proven otherwise by testing.
 
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Thanks everyone! As I said, already sent in the test and am waiting for results - in no way am I asking for anyone to do work without proceeding safely and in the right way. Was just curious about people's opinions when looking at this sort of thing.