we have noticed black residue at the a/c ceiling vent in one of the bedrooms. It has stained the popcorn ceiling to the point it is starting to peel. Where do we start in trying to address this.
If I call a ceiling, plaster repair, how will i know if the cause of the problem is fixed. I don't see any sides of moisture but i do worry it might be mold. Any advise is appreciated -thanks.