These salts can push paint away from the surface and peeling results. Efflorescence occurs on brick walls of new construction. A common building practice is to treat new brick or concrete with muriatic acid, rinsing with water to clean away excess mortar. Rinsing removes only those salts on or near the surface. After painting, salts remaining within the bricks will absorb the moisture and travel to the surface, causing peeling.
Peeling can also occur when alkyd or oil paint is applied over unetched concrete.
Alkyd resins that come in contact with a alkaline surface form a soap film between the concrete surface and the coating, called saponification. This will cause softness and loss of adhesion of the alkyd coating. If efflorescence is evident, it must be removed before repainting. First, remove all flaking or chalking paint from the damaged area by wire brushing or sandblasting. Rinse with clean water.