Efflorescence is characterized by which statement?

• A. Atmospheric salt residues that reduce adhesion and cause blistering, peeling, flaking and under film rusting.
• B. A solvent-based additive that improves gloss.
• C. A protective wax layer.
• D. A type of primer.

Answer: (A)

Efflorescence is the appearance of salt residues on a surface caused by moisture moving through a porous substrate and bringing dissolved salts to the surface. Those salts form a white, powdery film that can interfere with how coatings wet and bond to the surface. When you try to coat over this film, the salts hinder adhesion and create conditions that lead to blistering, peeling, and flaking of the film, and they can even promote under-film rusting if metal is present underneath. This description matches the idea of atmospheric salt residues causing adhesion problems and coating defects.

It isn’t describing a solvent-based additive for gloss, a protective wax layer, or a primer, so those options don’t fit the phenomenon of efflorescence.