Efflorescence on Brick: What It Means and What to Do
Efflorescence — the white, powdery or crystalline deposit that appears on brick, block, and stone surfaces — is one of the most common masonry conditions in Cleveland. It is also one of the most misunderstood.
What Causes Efflorescence
Efflorescence occurs when water dissolves soluble salts within the masonry or mortar and carries them to the surface. As the water evaporates, the salts are deposited on the face of the masonry. The three requirements are:
- Soluble salts present in the masonry, mortar, or soil
- Moisture to dissolve and transport the salts
- A pathway for the moisture to reach the surface and evaporate
All three conditions must be present. Eliminate any one of them, and efflorescence stops.
Is Efflorescence Harmful?
The salt deposits themselves are generally not harmful to the masonry. They can be brushed or washed off without damaging the brick. However, efflorescence is a reliable indicator that moisture is moving through the wall assembly — and that moisture movement is the real concern.
Persistent efflorescence indicates an ongoing moisture source that, if not addressed, will eventually cause:
- Mortar joint deterioration
- Freeze-thaw damage (spalling)
- Subflorescence (salt crystallization below the surface, which is destructive)
- Mold or rot in the wall cavity behind the masonry
Common Moisture Sources
- Rising damp: Ground moisture wicking up through the foundation
- Rain penetration: Through cracked mortar joints or failed flashings
- Condensation: Warm interior air meeting cold masonry
- Irrigation overspray: Sprinklers hitting the building
- Poor drainage: Water pooling at the base of the wall
How to Address Efflorescence
Step 1: Identify the Moisture Source
Do not just clean the surface. Determine where the water is coming from. The location and pattern of efflorescence often indicate the source — low on the wall suggests rising damp, high on the wall suggests rain penetration or flashing failure.
Step 2: Eliminate the Moisture Source
Fix the mortar joints, replace the flashing, correct the drainage, or address whatever is allowing water into the wall assembly.
Step 3: Clean the Surface
Once the moisture source is eliminated, clean the efflorescence with a stiff brush and water. For stubborn deposits, a dilute muriatic acid solution (1:10) can be used, followed by thorough rinsing. Always wet the wall before applying acid and rinse thoroughly afterward.
Step 4: Monitor
After cleaning, monitor the area for recurrence. If efflorescence returns, the moisture source has not been fully eliminated.
What Not to Do
- Do not seal the surface to prevent efflorescence. Sealing traps moisture inside the wall, which causes far more damage than surface salt deposits.
- Do not ignore it. Efflorescence is your building telling you that moisture is moving where it should not be.
- Do not power wash aggressively. High-pressure washing can drive water deeper into the masonry and damage the brick face.
Seeing white deposits on your masonry? Request a free estimate [blocked] or call (216) 213-5403.