Crusty white salt deposits, leached from martor or masonry as water passes through it.Possible Cause:
- Painting over insufficiently cured concrete.
- Excess moisture escaping through the exterior masonry wall from inside.
- Failure to adequately prepare surface by removing all previous efflorescence.
- If excess moisture is the cause, eliminate the source by repairing. Seal any cracks in the masonry.
- Remove the effloresence and all loose material with wire brush, power brush or power washer; then thoroughly rinse the surface.
- Seal off with compatible alkali resisting primer before painting.
- When efflorescence proceeds to the calcium carbonate phase, it becomes insoluble and is more difficult to remove-Perhaps impossible.
- The application of a mild acid solution becomes the first course of action. These acids include vinegar (5%Acetic Acid), Muriatic acid or citric acid.