I occasionally run across a black powdery substance on roof trusses and occasionally on floor joists. I found some again at an inspection last week on a roof truss and called it out as potential mold and it needs to be tested to determine the nature of the substance. The agent had the company she uses for mold related things come out and the guy told her it wasn’t mold. He gave her a tip that “if it wipes off with a sponge then its not mold and that it was likely dirt”. I was highly skeptical about the dirt diagnosis so I took a swab sample at another inspection when I found the same black powdery substance. I got the results back today and it is indeed mold - two different kids were present one that needs high moisture to grow.
So now I finally know what the substance is (don’t care much about that guy’s misdiagnosis) but how do I write it up in the future? The mold is not extensive and I usually only find it in a localized spot in the attic on a truss or two or the sheathing. Obviously there is a moisture issue allowing this to happen. Do I comment on cleaning the mold and then addressing the sources of moisture…which could be a lot of work diagnosing and correcting. Clean it up and hope it doesn’t come back? Rip the roof off and rebuild it a la Mr Holmes? LOL