Efflorescence

Causes

• Failure to properly prepare the surface by removing all previous salt deposits
• Excess moisture escaping through exterior masonry walls from the inside
• Painting masonry surfaces before they are fully cured

Solutions

• Remove the efflorescence and all other loose material (dirt, unbound sand and deteriorated paint, etc.) with a wire brush, a power brush or power washer; if a wire brush is used, follow by thoroughly rinsing the surface.
• Wash the surface with a solution of one part phosphoric acid to seven parts water (for safety, always add the acid to the water; never add the water to the acid). Citric acid is the safest and easiest to use; however, it is slightly less effective.
• Rinse thoroughly with clean water.
• Allow the surface to dry completely.
• If efflorescence still exists, repeat above steps.
• Seal the surface with a high-quality primer designed to hold back efflorescence.
• Repaint with a premium-quality acrylic finish.

Caution

Phosphoric acid will burn the eyes and skin. Always wear protective clothing, goggles, rubber gloves and boots when acid-washing.