Deterioration of the film of the applied paint or of a coating on the exterior caused by the action of the weather and atmospheric agents, resulting in a faded surface covered by a white powder which leaves marks when you run your fingers over the surface. Calcination occurs when the binder is degraded by adverse environmental conditions. You should make sure it is fully removed before repainting.

 

CAUSES: The alkalinity of the lime and cement of the plaster, which in the presence of a given humidity, reacts with the acidity characteristic of some paints. Overtime, by actions of the bad weather, the film of the paint starts to degrade, as well as by the action of the solar rays (Ultraviolet) that contribute to the degradation of the resin over time, causing this effect of calcination.

 

TREATMENT: Wash thoroughly with high pressure water to ensure the complete elimination of dust. Allow it to dry. Apply a suitable primer and give the final paint finish. To ensure that a paint or coating has a high durability and resistance to ultraviolet rays, you should use 100% Acrylic based products and pigments of high light fastness.