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Efflorescence!

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This information applies to efflorescence on all surface types,
including brick, block, tile, grout, slate, stone, concrete work, pavers, limestone, marble, granite, etc.

Efflorescence can be heavy as shown in these pictures or very light deposits in the pores of concrete products (block, manufactured stone, brick, pavers) that creates the appearance of fading.

Where it comes from! -- How to remove it! -- How to stop it!

First, please see this definition and discussion for a basic understanding of the process and condition.

Where does it come from?

Two conditions must be present to create efflorescence:

  1. A source of water soluble salts.
  2. Water moving through the material to carry the salts to the surface. The water evaporates and leaves the white powder behind.
Some surfacing products are more prone to have efflorescence because:
  • They might be more permeable and promote water travel.
  • They might tend to have higher water soluble salts in some batches.
Despite the best efforts of surfacing manufacturers to minimize water soluble salts in their products, they use materials from the earth that can vary from batch to batch.

The causes and treatments of efflorescence are the same, regardless of the material on which it appears. Flooring, roofing, walls and their component materials only vary in the product application technique, as described on product labeling.

Water sources can be:

  • IN/OUT - Entering at the surface (rain or sprinklers), penetrating in a fraction of an inch, then returning to the surface carrying the salts.
  • THROUGH - Entering from behind (bad flashing, caulking, leaks) or underneath (water from the earth migrating up) and traveling through.

There are two kinds of efflorescence.

  1. Regular "powdery" efflorescence as described above and is still gone after "Efflorescence Treatment" dries.
  2. "Crystalline" efflorescence. When powdery efflorescence goes through cycles of being deposited on the surface - re dissolved when new water occurs - drying out - new water - etc. it can form crystals. The crystals become tightly bonded to the surface. The crystals do not have to be thick. A light haze that is still there after using "Efflorescence Treatment" will be light crystal formation and is treated as described below.

These white stains and blooms are all efflorescence.
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clean, protect, seal tile - stone - pavers - brick
This is a worst case efflorescence condition. And - this is the interior wall! The extensive blooming was caused by long term, heavy water intrusion from bad flashing. The wall is the interior wall of "double wythe" construction. This is where two brick walls separated by an air gap serve as one structural wall. Within the air gap is a supply of water soluble salts that has lasted for years. Rainwater has been flowing into the wall gap and carrying salts out for a long time.
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efflorescence vs. mineral deposits

Is this efflorescence or mineral deposits?  It could be either or both. It appears to be a pattern from a sprinkler hitting the wall.  It could be minerals in the water that are left behind.  It could be the water soaking into the block wall and coming out again carrying internal salts.  Or, it could be both.

How can it be cleaned?

"Powdery" efflorescence only requires a simple application of Aldon "Efflorescence Treatment".

clean, protect, seal tile - stone - pavers - brick
Efflorescence Treatment

Before
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clay brick - charcoal color
After
clean, protect, seal tile - stone - pavers - brick
after 15 minutes
  • "Efflorescence Treatment" is not a cleaner that must be rinsed or removed.
  • "Efflorescence Treatment" carries the salts below the surface.
  • "Efflorescence Treatment" enhances the surface color.
  • See the "Efflorescence Treatment" page in the PRODUCTS section for more pictures and details.

"Crystalline" efflorescence can not be moved by "Efflorescence Treatment" because of the crystal's attachment to the surface. That is why you may treat a surface with "Efflorescence Treatment" and it looks great for a few hours. But then, when it dries you can see some efflorescence deposits remaining. They are not new deposits coming out. They were just temporarily disguised by the darkening effect of the initial treatment. The reappearing efflorescence is crystalline and is bonded to the surface. These deposits will "fizz" on contact with a strong acid (pool acid, muriatic acid), but do not use that acid for cleaning. A safer, but just as strong product to remove the deposits is:

  1. First - remove crystal deposits with Aldon
    clean, protect, seal tile - stone - pavers - brick
    Grout Residue
    Remover
  2. Note: If there is no fizzing reaction and the crystals are not removed, this is not efflorescence.
    • Possibility #1: See Problem Solving for "additive" bleed out.
    • Possibility #2: There are a few brick manufactured in the southeastern United States that can bleed out a chemical deposit that is very difficult to remove. Removal options may be limited to a type of sand or shot blasting.
  3. Then - treat with Aldon "Efflorescence Treatment" for any remaining powdery efflorescence and to enhance surface color.
Before

This concrete paver shows efflorescence, crystalline efflorescence, and scuffing.

Concrete paver with efflorescence and scuffing
After cleaning treatments. Yes, this is the same piece.

First with "Grout Residue Remover" to remove crystalline efflorescence and scuff marks.

Then treated with "Efflorescence Treatment". Note how the color has been restored.

Concrete paver after cleaning and color restoration

Tip about sealed surfaces: typically efflorescence would be below the sealer (not in it) because it comes up from inside. Mineral deposits would be on top of the sealer as residue of drying water. If on top, it will wipe off. If below the surface, the sealer needs to be removed to access the white stuff for treatment, unless Efflorescence Treatment is able to penetrate through the sealer.

How it can be stopped!

After treating the surface to restore its appearance, you can prevent future efflorescence by applying one of Aldon's penetrating sealers per directions. This is true even if the water is coming from behind or subsurface and cannot be stopped.

Laboratory Test Proving:
Efflorescence Can Be Stopped By Aldon Sealers!

Test Procedures:

  • Using a red clay brick - designation: "Common". The dark color and high permeability show efflorescence easily.
  • The brick is partially submerged in a pan of water with 5% sodium carbonate (water soluble salt).
  • The Pan is covered with plastic wrap with a hole cut at the brick face only. This forces water to migrate through the brick.
  • A fan is blowing air across the surface to accelerate the water migration.
  • These conditions are worse than most real world situations.
  • All brick are from the same pallet to minimize differences.
  • The "control" brick shows what happens with no Aldon sealer.
"Control" Brick
Unsealed - "raw"
At 2 minutes
No efflorescence

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"Control" brick - "Raw"
12 hours later and allowed to dry
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Test #1

A = "SBS Sealer"
B = raw
C = "Porous Stone Sealer " (The same result is achieved with "Penetrating Paver Sealer".)

Efflorescence stopped!

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Test #2

A = "Mexiglaze"
B = raw

Efflorescence stopped!

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Test #3

A = "Same Day"
B = raw
C = "Crystal Glaze"

Efflorescence stopped!

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*Note arrow and see below.
* The arrow on Test #3 picture points to slight efflorescence on the left edge of the "Crystal Glaze" section. As "Crystal Glaze" is a "coating" type sealer and does not penetrate to the degree of the others, it is somewhat less effective in stopping efflorescence if the water source is subsurface as in this test. However, as it will impede the entrance of outside water (rain, sprinkler), the in/out cycle of that water source is broken - which stops efflorescence.
How does this work?

The Aldon penetrating sealers create a barrier below any absorbent surface that allows water vapor to "breathe" out, but stops the water soluble salt molecules from migrating out.
Note: You can have efflorescence after sealing with another companies sealer, so do not expect the results from an Aldon sealer to apply to all sealers.

If white stains appear after properly sealing an Aldon installation, they are not efflorescence. They are probably mineral deposits from rain water runoff or sprinklers that are on top of the sealer. See  clean, protect, seal tile - stone - pavers - brick  regarding cleaning.

Painting the finish:

As you saw above, you need the sealer penetrated down below the surface to stop efflorescence.  The problem with then painting the surface is that the sealer can be a "bond breaker" and might not provide good adhesion for the paint.

Note: There are paint store products termed "primer/sealer" for paint. These are a surface coating preparation step for paint adhesion and finish. They are not a sealer of the types that Aldon manufactures that function as a final sealer that provides multiple benefits of the kind we have described, including the creation of an efflorescence barrier below the surface.

 If you really must paint the surface in addition to sealing it, take the gloss down to the surface and then use sandpaper to roughen up the surface to improve the "grabbing" ability of the paint.

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