11/03/2026
Black, crumbly material under old carpet — asbestos concern?
1950s house; passed through multiple owners and renovations, carpet and underlayment appear to be 20-30yr old
I’m renovating a fixer-upper and removing the flooring from a garage that was converted into a living space by the previous owners.
Under the laminate tongue-and-groove flooring, I found a layer of insulation and some nasty-looking carpet that’s probably 30–40 years old.
Beneath the carpet is a thin, black, powdery, crumbly material stapled to the plywood subfloor.
My initial guess is asphalt-saturated felt underlayment or some type of moisture barrier or sound-dampening material.
It doesn’t strike me as a typical asbestos-containing material, but I know appearances can be misleading. I’m planning to get it tested before proceeding with demolition.
Has anyone encountered something similar? Any idea what this material might be, and whether asbestos is a common concern with it?