Efflorescence

Efforscence

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.

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.

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".

• "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. 
   

"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 Grout Residue Remover.
2. Note: If there is no fizzing reaction and the crystals are not removed, this is not efflorescence. 
3. Then - treat with Aldon "Efflorescence Treatment" for any remaining powdery efflorescence and to enhance surface color.

 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. 

 

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.

Painting the finish: 

You need the sealer penetrated down below the surface to stop efflorescence.  The problem with then painting the surface is that the sealer is a "bond breaker" and does not provide good adhesion for the paint. If you really must paint the surface also, take the gloss down to the surface and then use sandpaper to roughen up the surface to improve the "grabbing" ability of the paint.