Is this black stuff mold on the concrete foundation?
In the process of replacing the bath/shower plumbing and fixtures I started chasing mold from the surround. As I followed the trail underneath the laminate floor, I saw all this blackness. It was very damp under the floorboards, and I know I had mold in the bathroom. Just wondering if it might be some sort of concrete sealer or pre-floor coating or glue from a previous flooring. Hoping it's not all mold...
Thoughts? Thanks!