As in steel the concrete and masonry surface also need to be protected, these surfaces are porous and therefore absorb moisture and atmospheric impurities, which corrode the steel reinforcement. Concrete and masonry surface also developed Fungi and Algae. Such surface get abraded over a period, if not protected properly.

The concrete masonry surface should be clean from contaminates like grease, oil, scale, etc. If presents, by washing with 10% caustic soda solutions.

It is then subjected to acid etching with 10% Hydrochloric Acid and washed throughly with fresh water. Surface should be allowed to dry completely before painting.