What is efflorescence?
Efflorescence is a white, chalky mineral deposit that appears on masonry surfaces when salt-laden moisture reaches the surface and evaporates.
Efflorescence shows up as a white or gray powdery coating on brick, stone, concrete, or mortar. It forms when water moves through the masonry material, dissolving salts that naturally occur in the brick, stone, mortar, or soil. As that moisture reaches the surface and evaporates, it leaves the salts behind as a visible deposit.
The phenomenon signals active moisture movement through the masonry. In new construction or after heavy rain, efflorescence often appears on brick masonry and stone work. While the deposit itself is not harmful to the material's structure, it indicates water is traveling through the wall assembly, which could point to drainage problems, improper grading, failed caulking, or mortar joints that need attention.
Efflorescence typically fades as the salts become exhausted, but persistent or heavy deposits suggest ongoing moisture intrusion. Early detection helps identify whether water is entering from exterior sources (rain, groundwater) or being transported upward from below. Understanding where and how often efflorescence appears on a building tells you where moisture control may need improvement before more serious damage like freeze-thaw damage or interior water stains develops.