What Causes Black Soot On Walls. Corroded drywall screws and fasteners cause patterned, similarly sized black spots. Soot, sometimes called lampblack or carbon black, is a fine black or brown powder that can be slightly sticky and is a product of incomplete combustion.
The size of those tiny particles is directly linked to the terrible trouble they cause.
Black marks on walls have a variety of causes, ranging from simple scuff marks to mold. Scientists have uncovered strong evidence that soot, or black carbon, sent into the air by a rapidly industrializing europe, likely caused the abrupt retreat when black carbon particles settle on snow, they darken the surface. The bathroom side of the wall had no holes. The sooty substance is actually called sooty mold, and it is a fungus that is spread by insects.