How to Remove Efflorescence & Clean Bricks

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Plus, learn what causes efflorescence and how to prevent it
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Efflorescence is the result of water-soluble salts building up over time on the porous surface of bricks, and while it isn’t harmful, it also isn’t visually appealing. Luckily, it’s easy to remove efflorescence from brick in a few simple steps. In this article, we’ll teach you how to remove and prevent efflorescence , with tips from cleaning experts and landscapers. Plus, learn what causes efflorescence and get answers to other common questions about it.

How do you get rid of efflorescence?

If the affected area is small, scrub the efflorescence with a dry, stiff-bristled brush to sweep it away. If the area is larger or the efflorescence is stubborn, dip the brush into a mixture of dish soap and water or water and white vinegar. In extreme cases, try applying muriatic acid or using a sandblaster.

Section 1 of 7:

Removing Efflorescence from Brick

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  1. In mild cases, efflorescence can be removed simply by brushing the dry surface. Grab a dry, stiff-bristled nylon brush or a wire brush and scrub it against the surface to sweep away the efflorescence. Because efflorescence is powdery, wear a dust mask to protect your lungs. [1]
    • Using a dry brush is most effective if the efflorescence is only in small patches. If there’s a large area of efflorescence, you may need to use a stronger method.
    • It's good to avoid water if you can help it, because water is what causes efflorescence.
  2. Cleaning expert Melanie Garcia says an exterior brick surface “can usually just be sprayed down with a water hose.” [2] For interior surfaces, use a spray bottle filled with water to wet the surface. Then, use a stiff brush and mild dish detergent to scrub away the powder. Rinse the soap off with fresh water. [3]
    • Once the brick is dry, check to see if the efflorescence is gone. If it isn't, you may need to repeat this or try a stronger cleaning solution.
    • When treating an outdoor wall, make sure the temperatures will be above freezing all day.
    • If you’re cleaning bricks outside, another option is to use a pressure washer . Use the widest-angle tip that works without damaging the surface.
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  3. Vinegar can be abrasive on old bricks, so only use this method if your bricks are less than 20 years old. Mix equal parts of water and white vinegar in a spray bottle. Spray the solution onto the surface and let it sit for 5 minutes. Then, spray the bricks with the mixture again and use a stiff brush to scrub away the efflorescence. Scrub in small, circular motions before rinsing the surface with fresh water. [4]
    • Neutralize the acidity of vinegar by mixing a solution of 2-3 tablespoons (30-45 g) of baking soda with a spray bottle full of water. Spray the solution onto the bricks you treated with vinegar. Then, rinse the area with clean, warm water.
  4. If natural solutions don’t work, consider buying a commercial efflorescence remover . Many of these products are acid-free and designed specifically to remove efflorescence, salt deposits, lime, and rust stains from brick and other surfaces. Most of these products are also safe to use indoors. Follow the instructions on the package to apply them correctly. Here are some popular products to try:
  5. Sandblasting is a traditional method of cleaning brick. [5] Put on a face shield, rubber gloves, boots, and clothing that covers your arms and legs. Put down drop cloths to protect the surrounding area, and fill the blasting bucket with fine media . Set the sandblaster to the lowest setting and use it to wash away the efflorescence from a distance of at least 5 inches (13 cm). Go back and forth across the bricks using smooth, horizontal movements.
    • Note that a sandblaster will wear away the surface of the bricks, so only use it if you’ve already attempted gentler methods of removal, and avoid sandblasting brick that’s over 20 years old.
    • A sandblaster will remove more buildup than other methods but it also makes the brick more susceptible to efflorescence later on.
    • When you’re done, sweep, shovel, or vacuum up any dust and debris from the blasted area. Then, apply a brick sealant to your brick surface. Work from the bottom of the surface up, following the instructions on the package, and keep the surrounding area covered with drop cloths while you apply it.
    • If you don't feel comfortable using a sandblaster on your own, a contractor should be able to take care of it.
  6. Landscaper Tony Hoang stresses, “For safety, use chemical-resistant gloves and goggles” when handling muriatic acid. [6] Mix 1 part muriatic acid with 12 parts water. Presoak the wall with fresh water, then apply the acid mixture using a stiff brush. Let the mixture soak into the brick for about 5 minutes. Then, rinse the brick surface with plain water. [7]
    • Always wear protective equipment when working with acid.
    • Warning: When mixing the solution, always pour acid into water, never water into acid. Pouring water into acid releases a large amount of heat and can cause the acid to splatter and burn you. Adding acid to water, on the other hand, allows the heat to be absorbed.
    • Be aware that muriatic acid can stain or burn masonry, etch mortar joints, and cause premature deterioration through water penetration. Consider safer solutions instead, or call a professional to address the efflorescence.
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Section 2 of 7:

What is efflorescence?

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  1. This includes surfaces such as brick, concrete, and stucco. Efflorescence typically looks like a white or grayish powdery substance. It occurs when water evaporates into porous materials, leaving behind salts. [8]
Section 3 of 7:

Is brick efflorescence harmful?

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  1. Efflorescence does not damage the foundation or strength of your walls or floors. It also isn’t harmful to breathe in, as it’s simply a mineral deposit. However, the presence of efflorescence can indicate a moisture problem, which can lead to mold growth, so it’s important to address any underlying issues as soon as possible. [9]
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Section 4 of 7:

What causes efflorescence?

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  1. Three conditions need to exist for efflorescence to occur: there are water-soluble salts in or on the material, moisture is present to make the salt a soluble solution, and the moisture evaporates as the salts move to the material’s surface. This causes the salt to crystallize, which forms efflorescence. [10]
  2. In many cases, efflorescence occurs during home construction when materials are left outside overnight to absorb moisture or because building materials are installed incorrectly. Here are some common installation problems that may lead to efflorescence: [11]
    • Using construction materials that are poor quality or not fit for the purpose
    • Improper ground storage of building materials (ex: storing on damp soil or ground moisture)
    • Use of masonry without sufficient ventilation
    • Use of masonry in areas that lack a proper moisture barrier
    • Joint material failure
    • Improper construction techniques that could lead to structural damage
    • Environmental factors and climatic conditions, such as high humidity, heavy rainfall, or frequent freeze-thaw cycles
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Section 5 of 7:

Troubleshooting Efflorescence

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  1. The age of a structure can often help you determine what caused the efflorescence. If the structure is under a year old, the efflorescence source is likely the building material itself or water that entered the structure during construction. If the structure is over a year old, there may be a new source of water in the building material. In this case, examine the structure for leaks. [12]
    • Troubleshooting efflorescence is important because it allows you to determine the possible reason behind it so you can decide how to remedy the situation.
  2. Examining the location of the efflorescence may help you determine the water source that is causing the issue. Consider the recent use of the building as well. For example, if a building has been vacant for several months, various moisture conditions could have occurred and contributed to efflorescence. [13]
  3. Carefully look at the building material to determine if there are any cracks or other defects that could have led to efflorescence. Moisture may have entered through these crevices, so it’s important to take care of any issues you notice. [14]
  4. Examine wall sections and construction details to identify any potential moisture travel paths or the presence of salts. Check the roof and wall juncture and flashing details to help determine the severity of the problem and what to do to solve it. [15]
  5. Efflorescence can be caused by several water sources, like condensation within a wall, leaky pipes, and faulty drains. [16] To identify all potential sources, consider conducting an extensive condensation analysis, especially if you can’t find any visible sources.
  6. If possible, review lab reports to determine if soluble salts are present in the building materials and the surrounding area. The reports should provide valuable insights that may help you identify efflorescence and other potential issues. [17]
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Section 6 of 7:

Preventing Efflorescence

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  1. Applying a water-repellent sealant to a building material’s surface can help protect the material from absorbing moisture from rain or snow. Be sure to choose a sealant designed for preventing efflorescence , and apply it according to the instructions on the package. [18]
    • Hardscaping specialist Sina Kamran shared some advice on sealing a brick driveway: “There are specialty brick sealers. Some can even give it a bit of shine, like medium or high gloss. Pressure wash [the brick] first, then let it dry for two or three days. Depending on the type of sealer, apply it with a sprayer or roller.” [19]
  2. If you’re constructing something, make sure to store all your building materials properly. Avoid leaving them on the ground, especially overnight, as they’ll soak up the moisture from damp soil. Cover your materials with waterproof sheeting and store them on pallets to protect them from the elements and prevent them from absorbing excess water or salts. [20]
    • Protect newly built brickwork from the elements for the first week to help prevent efflorescence.
  3. Installing capillary breaks, like polyethylene sheeting , between the building materials and the soil helps minimize the risk of salt entering the material. This is also sometimes known as vapor barrier sheeting. [21]
  4. Make sure the building includes eaves, overhangs, and flashing to reduce the chances of water entering the walls, and make sure landscape plans include adequate runoff areas so water moves away from the masonry. [22]
  5. Mechanical vibrations and dense mortar joints can help remove empty spaces within the grout and reduce porosity. This slows the travel of water and salts between bricks, blocks, or stones, which can prevent efflorescence . Certain grout admixtures can also improve the flow of a grout mix and reduce its water content. [23]
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Section 7 of 7:

Efflorescence FAQs

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  1. 1
    Can efflorescence be removed permanently? It usually isn’t possible to remove efflorescence permanently. Efflorescence is a natural buildup of salts due to moisture exposure, so while it’s possible to remove it, it will typically come back when more moisture is introduced to the area. You can, however, address any underlying moisture issues and seal the masonry to help prevent efflorescence in the future. [24]
  2. 2
    How long does it take for efflorescence to go away? Because efflorescence is a natural process, it often fades on its own over time. When left alone, efflorescence will typically fade within a few months to a year as the salts within the material become exhausted. The exact timeframe depends on factors like climate, material porosity, and the severity of the efflorescence. [25]
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      Warnings

      • Always wear protective gear (like goggles, a face mask, and rubber gloves) when handling acid or using a sandblaster.
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      • Never pour water into acid, as it may splatter and burn you.
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      References

      1. ↑ https://www.masonryinstitute.org/pdf/612.pdf
      2. ↑ Melanie Garcia. Professional House Cleaner. Expert Interview. 10 October 2019.
      3. ↑ https://www.masonryinstitute.org/pdf/612.pdf
      4. ↑ https://www.apartmenttherapy.com/how-to-clean-a-brick-fireplace-with-all-natural-cleaners-apartment-therapy-tutorials-216668
      5. ↑ https://www.masonryinstitute.org/pdf/612.pdf
      6. ↑ Tony Hoang. Landscaping Manager. Expert Interview. 17 February 2022.
      7. ↑ https://www.bobvila.com/articles/how-to-clean-brick/
      8. ↑ https://www.nachi.org/efflorescence.htm
      9. ↑ https://www.nachi.org/efflorescence.htm
      1. ↑ https://www.gobrick.com/media/file/23a-tn23a.pdf
      2. ↑ https://www.masonryinstitute.org/pdf/612.pdf
      3. ↑ https://www.gobrick.com/media/file/23a-tn23a.pdf
      4. ↑ https://www.gobrick.com/media/file/23a-tn23a.pdf
      5. ↑ https://www.gobrick.com/media/file/23a-tn23a.pdf
      6. ↑ https://www.gobrick.com/media/file/23a-tn23a.pdf
      7. ↑ https://www.gobrick.com/media/file/23a-tn23a.pdf
      8. ↑ https://www.gobrick.com/media/file/23a-tn23a.pdf
      9. ↑ https://www.nachi.org/efflorescence.htm
      10. ↑ Sina Kamran. Hardscape Specialist. Expert Interview. 7 Nov 2023.
      11. ↑ https://www.nachi.org/efflorescence.htm
      12. ↑ https://www.nachi.org/efflorescence.htm
      13. ↑ https://www.gobrick.com/media/file/23a-tn23a.pdf
      14. ↑ https://www.gobrick.com/media/file/23a-tn23a.pdf
      15. ↑ https://www.gobrick.com/media/file/23a-tn23a.pdf
      16. ↑ https://www.theenvironmentalblog.org/2025/01/efflorescence-what-it-is/
      17. ↑ https://www.gsa.gov/node/1100?Form_Load=88552

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