Efflorescence – Mottling: Efflorescence is the formation of crusty, white salt deposits, leached from mortar or masonry
as water passes through it.
Failure to adequately prepare surface by removing all previous efflorescence.
Excess moisture escaping through the exterior walls from the inside.
If excess moisture is the cause, eliminate the source by repairing the roof, cleaning gutters and downspouts and sealing any cracks in the masonry using a quality water-based all-acrylic or siliconized acrylic caulk. If moist air is originating inside the building, consider installing vents or exhaust fans, especially in kitchen, bathroom and laundry areas. Remove all efflorescence and loose material from the masonry with a wire brush, power brush or power washer; then rinse. Apply a masonry sealer and allow it to dry completely; then apply a coat of top quality exterior house paint, masonry paint.