Efflorescence & Waterproofing · Chicagoland, IL
Why Efflorescence Keeps Coming Back — And What Actually Stops It
Efflorescence on brick buildings is one of the most commonly misunderstood masonry problems — property owners clean it off repeatedly without realizing that the cleaning itself changes nothing. Understanding why it comes back is the first step toward actually stopping it.
2026-05-20
The Cleaning Cycle That Goes Nowhere
Here's the pattern we see repeatedly on commercial and residential brick buildings in the Chicago suburbs: a property manager or owner notices white chalky deposits on the brick face, hires someone to clean them, the cleaning works temporarily, and within one or two wet seasons the deposits are back. Sometimes worse than before.
This cycle can repeat for years. Each cleaning removes the surface evidence of the problem without touching the cause. As long as water continues to move through the masonry, the deposits will keep forming. Cleaning is maintenance of the symptom; stopping efflorescence requires treating the cause.
What Efflorescence Actually Is
Efflorescence is the surface crystallization of soluble salts that are carried to the exterior face of the wall by water moving through the masonry. The source of the salts is the masonry materials themselves — primarily calcium carbonate (from lime in the mortar), calcium sulfate, and other mineral compounds present in both brick and mortar.
When water infiltrates the wall through a failed joint, cracked coping, or open flashing, it dissolves these salts as it moves through the masonry. When the water reaches the exterior face and evaporates, the salts remain — deposited as the white crystalline or powdery deposits that property owners find on their brick.
The salt deposits themselves are chemically inert and don't damage the masonry. The water that carried them there does.
Why Cleaning Doesn't Fix It
Acid washing (diluted muriatic acid or commercial efflorescence removers) dissolves the surface salt deposits and rinses them away. This is appropriate surface prep for specific situations — primarily before applying a sealer after repairs are complete — but it does nothing to interrupt the water movement causing the deposits.
Several things happen after cleaning that cause the deposits to reappear quickly:
The water entry point is still open. Whatever failed joint, cracked coping, or deteriorated flashing is allowing water in is still open. The next rain event starts the cycle again.
The cleaned pores are more susceptible to salt deposit. An acid wash removes not just the surface salts but some of the fine particulates on the brick face, leaving a slightly more porous surface that wets more readily.
Power washing can worsen joint condition. Pressure washing drives water into already-compromised joints, potentially deepening the water infiltration path that caused the deposits in the first place.
The Actual Causes — By Pattern
Efflorescence patterns on a building tell you where the water is entering, which tells you what needs to be repaired.
Deposits Starting at the Parapet Line and Running Down
The coping joints at the top of the parapet are open. Water is entering the wall at the highest exposed point and migrating down through the brick. This is the most common pattern on flat-roof commercial buildings in the Chicago area.
What repairs it: Repointing the coping joints and parapet face tuckpointing.
Deposits Along Horizontal Lines at Regular Intervals (Multi-Story Buildings)
Failed mortar at a specific course or elevation — often at a floor line, shelf angle, or previous repair seam — is allowing water infiltration at that level. The deposits follow the water's path from the entry point to the face.
What repairs it: Targeted repointing at the entry point elevation, combined with full wall assessment to identify the specific failed joint level.
Heavy Deposits at Grade Level
Ground moisture, splash from paving, and ice melt are penetrating joints at the base of the wall. This is common on lower courses of any building, but particularly on north and east elevations that stay wet longer.
What repairs it: Grade-level repointing from the foundation to approximately 18" above grade, attention to weep holes if the wall is a veneer system, and assessment of whether grade and drainage around the building is directing water toward the wall.
Deposits Below Window and Door Openings
The sill flashing, sill joints, or mortar at the window frame perimeter has failed. Water is entering at the window rough opening and exiting through the brick face below.
What repairs it: Repointing the window perimeter joints, assessing and replacing failed sill flashing if present.
Spotty Deposits Scattered Across the Wall Face
Scattered efflorescence without a clear pattern often indicates multiple minor entry points across the joint pattern — the wall is uniformly past its tuckpointing threshold and joints are eroding broadly.
What repairs it: Full-building tuckpointing.
The Correct Repair Sequence
Once you've identified the pattern and the likely entry points, the sequence is:
1. Repair the entry points. This is the only step that actually changes the outcome. Repoint the failed joints, replace damaged coping, address flashing, fix the drainage issue — whatever the specific cause. Nothing downstream from this step matters if you skip it.
2. Allow repairs to cure. Mortar needs approximately 28 days to reach full strength. Applying sealer over fresh mortar traps moisture in the repair and weakens it.
3. Clean the efflorescence deposits. After repairs have cured, use a diluted efflorescence cleaner (diluted muriatic acid or a commercial equivalent). Pre-wet the brick before application to prevent acid absorption. Apply, scrub, neutralize with a baking soda solution, and rinse thoroughly. On brick that has been subjected to years of repeated deposits, a second cleaning pass may be necessary.
4. Apply a penetrating sealer. After the wall is clean and dry, apply a silane-siloxane penetrating sealer to the repaired sections or the full wall face. This creates a hydrophobic barrier inside the brick and mortar pores without trapping vapor — critical on older masonry that needs to breathe. A properly applied sealer on sound masonry after repair reduces future water infiltration and gives the masonry longer intervals between maintenance cycles.
5. Do not apply film-forming coatings. Elastomeric paint, waterproof coatings, and similar film-forming products trap moisture vapor inside the wall. In Illinois winters, trapped vapor expands into ice and causes spalling. Film coatings on historic or soft brick cause accelerating damage. They are not appropriate for brick buildings in freeze-thaw climates.
When Persistent Efflorescence Indicates a Bigger Problem
In most cases, efflorescence is a mortar joint or coping maintenance issue — repairable without structural intervention. But certain patterns indicate more serious underlying conditions:
Efflorescence combined with brick face delamination — if the brick faces adjacent to the deposits are also spalling, water has been cycling through the wall long enough to degrade the brick itself. Brick replacement and full-scope restoration, not just repointing, is likely needed.
Heavy deposits at a single location despite previous repointing — if the same location continues producing deposits after the surrounding joints have been repaired, the source may be internal — a deteriorated through-wall flashing, a concealed crack, or a drainage problem internal to the wall cavity. This requires more investigation than a standard repointing scope.
Deposits on the interior face of the wall — if efflorescence is appearing on the interior surface of a masonry wall (in a basement or unfinished space), water is moving through the full wall thickness. This indicates more significant infiltration than surface joint failure and may require investigation of the drainage and waterproofing system at the foundation level.
FAQ
My building was cleaned and sealed two years ago and the deposits are back. What went wrong?
Almost certainly one of two things: the entry points weren't repaired before the sealer was applied, or the sealer was applied over failed joints that allowed water through the sealer layer. Sealer applied without prior joint repair doesn't stop water — it creates a harder-to-fix version of the same problem. The correct diagnosis requires looking at where the new deposits are originating and whether the sealer is still intact in those areas.
Will efflorescence damage the brick permanently?
The salt deposits themselves don't damage brick. Long-term water cycling does — through freeze-thaw spalling and mortar erosion. Buildings with persistent untreated efflorescence are buildings where water is moving continuously through the masonry, which means freeze-thaw damage is accumulating with every Illinois winter.
For a free on-site assessment of efflorescence sources and repair recommendations, contact Emerald Masonry LLC at (708) 288-1696 or emeraldmasonryil@gmail.com.