What Causes of Efflorescence in Bricks?

Efflorescence in bricks is caused by three key factors: moisture, soluble salts, and evaporation. When water enters a brick wall - through rain, rising damp, leaks, or construction moisture - it dissolves naturally occurring salts within the bricks, mortar, or adjacent materials. As the water moves through the porous structure and reaches the surface, it evaporates, leaving behind white, powdery salt deposits.

This often happens during or shortly after construction when materials are still drying out, especially if bricks or mortar have absorbed water on-site. Poor drainage, inadequate damp-proofing, or improper sealing can make the problem worse by allowing continued moisture intrusion. Efflorescence is not usually a structural issue on its own, but it’s a clear signal that water is migrating where it shouldn’t, making it important to address the source of moisture before further damage occurs.

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