Efflorescence: Crusty, white salt deposits leached from masonry or mortar as moisture passes through.
Efflorescence causes: Excessive moisture. Inadequate venting of interior moisture laden areas. The pH level too high or the lack of curing time. Excessive lime in concrete mix. Soluble salts in masonry when dissolved by water appear on the surface as crystallized salts.
Efflorescence solutions: Requires the elimination of moisture sources. Remove all loose paint and other particles with a wire or stiff brush before repainting. Fill all cracks with a masonry patching compound. Repair any leaks or other moisture sources.
Primers & exterior finishes: Masonry primer/sealer is essential and must dry completely before repainting. Select a top quality exterior paint in the color and sheen of your choice.