A common problem that often arises with newly installed pavers is the appearance of a white haze that won't seem to come off. The most likely cause of this is a naturally occurring phenomenon called efflorescence.
You can try cleaning the pavers with a mixture of water and mild detergent. Another option is to hire a power washing company to do a low-pressure wash. Other more aggressive options include sandblasting and a chemical cleaning. We always recommend you hire a professional to ensure you do not damage your pavers.
Just as it appears naturally, efflorescence will eventual- ly disappear. Over time, rainwater can wash and wear it away.
The calcium carbonate creates the whitish haze on the surface of the concrete pavers. As the moisture evaporates off the surface of the pavers, the whitish haze becomes more pronounced. And as naturally as the efflorescence appeared, it will fade.
Try Concrete Stain
The simplest path to reviving tired pavers is to apply an acrylic-based semitransparent concrete stain, such as Behr Premium Semi-transparent Concrete Stain ($27/gal.; Home Depot) or Valspar Semi-transparent Concrete Stain ($28/gal.; Lowe's).
Over time, the continuous high-pressure blast of water will erode the layer of color on the pavers and expose the stone and aggregate contained in them. Oftentimes, the stone and the aggregate do not retain the color of the pigments used and will appear dull.
Once again, acetic acid will wreak havoc with your block paving. Porous stones like limestone and sandstone are more susceptible to damage than most, as the vinegar can seep into the stones themselves, though even sealed and non-porous stones can discolour and bleach.
Now the misconception is that the pavers themselves have turned white. It's actually moisture that is trapped underneath a coating of sealant. Our sealers are breathable, so they allow that moisture to escape so you don't have that issue.
The result is a deposit or 'salt' that appears on the surface of the paving. There's no single, definitive appearance - it is sometimes powdery, sometimes scummy: sometimes it's hazy and indistinct; sometimes it's sharp, crisp and obvious.
This form of efflorescence generally lasts around two to three years and fades naturally as the salt supply decreases. Salts are carried to the surface of concrete or brickwork by hydrostatic pressure or osmosis/evaporation, and deposited when the water evaporates, resulting in this type of efflorescence.
Efflorescence alone does not pose a major problem, but it can be an indication of moisture intrusion, which may compromise the structural material. Building materials, such as concrete, wood, brick and stone, are porous materials. Porous materials can absorb or wick water by a process called capillary action.
It is common for people to confuse mold with efflorescence. Efflorescence itself isn't dangerous or harmful. It can lead to potential moisture problems that can cause structural damage to building materials.
The acidity in the vinegar helps remove the efflorescence and calcium deposits by breaking down mineral crystals. After cleaning the surface, let dry for 48-72 hours (moisture content below 25%).
In many cases, efflorescence will disappear on its own over time (usually after the first year of a paver or retaining wall installation).
Simple washing can sometimes remove efflorescence. Scrub with a stiff brush and mild detergent or plain water. Efflorescence is most soluble when it first appears, so sooner is better than later if you want to try this approach.
The good news is that efflorescence is completely harmless, not detrimental to the blocks, can be removed and will gradually disappear over time. For further information please take a look at our Literature section for our Efflorescence Block Paving Factsheet.
A few major differences between efflorescence and mold growth: Mold grows, efflorescence doesn't. Mold can grow on just about any surface, whereas efflorescence doesn't spread. Mold is a fungus, whereas efflorescence is moisture that evaporates into salt deposits.
Most people confuse secondary efflorescence with mold because it looks like a white, dusty mold growing on your concrete. However, it is not mold but rather an indication of a water problem at hand—and where there is water, there is mold and potential structural damage.
It is caused by water carrying salts to the surface, where they evaporate and leave behind the white residue. Efflorescence is not harmful to your pavers or travertine, but it can be unsightly. Sealing your pavers or travertine can help reduce the amount of efflorescence that forms.
Why is my concrete turning white? Efflorescence is a white salty residue caused when too much moisture is moving through the concrete. As the concrete dries and its moisture rises upwards through the slab, it brings salts within the concrete to the surface as well.
Baking soda has low-abrasive properties, making it an excellent cleaning material for stuck-on grime and tough stains. Additionally, baking soda is absorbent, allowing it to absorb oils from the surface of the pavers, especially freshly oil spill on concrete pavers.
To clean paver slabs, you can use a detergent, such as Dawn, or a vinegar-water solution that is gentle enough to effectively clean without causing damage to your concrete pavers.
It is common to mix bleach with water; however, you can also add other ingredients to make it more effective. Avoid an intense concentration of bleach, as it can damage the pavers.