Celotex sheathing

Anyone familiar with this product. It’s a Celotex fiber board used as interior sheathing on a house built in 1940. I’m wondering it is likely to also contain asbestos?



If it’s the black fiberboard, probably not. The only Celotex brand material that I think contained asbestos were the wraps produced for insulating piping. To be sure, send a sample off to a lab.


interior sheathing? in place of drywall?

Jeffrey, it’s just brown, both sides.

Robert, yep, interior sheathing, no drywall. Although the label says it can be used as lath, they mostly just wallpapered over it.

I have already removed a sample to send in for testing. Just thought I’d see if anyone had first-hand knowledge of the product first.

any suggestions for reliable labs to send it to, with halfway decent response times? Or just pick one and go?

thanks again,


EMSL is where I send Asbestos samples. Also had good service from the them.

Hi Dan,

I found the same type of Celotex sheathing in my bathroom. Did you send a sample to have tested? If so, will you share the results?

Thank you!