Efflorescence and Mottling

Crusty, white salt deposits, leached from mortar or masonry as water passes through it.

Possible Cause

• Failure to adequately prepare surface by removing all previous efflorescence.
• Excess moisture escaping through the exterior masonry walls from the inside.

Solution

If excess moisture is the cause, eliminate the source by repairing roof, cleaning out gutters and downspouts, and sealing any cracks in the masonry with a high quality, water-based all acrylic caulk. If moist air is originating inside the building, consider installing vents or exhaust fans, especially in kitchen, bathroom and laundry areas. Remove the efflorescence and all other loose material with a wire brush, power brush or power washer; then thoroughly rinse the surface. Apply a quality water-based or solvent-based masonry sealer and allow it to dry completely, then apply a coat of top quality exterior house paint, masonry paint or elastomeric wall coating.

Images courtesy of the Paint Quality Institute from Dow Coating Materials