Have you noticed a white and fuzzy substance along your basement wall? If so, you’ve got efflorescence. While it is a common issue in concrete and masonry block foundations, it can occur on any porous surface, such as wood or stucco.
While efflorescence is usually white, it can vary in color depending on the salt involved and any associated chemicals. These salts include:
- Calcium sulfate
- Potassium sulfate
- Sodium sulfate
- Vanadyl sulfate
- Calcium carbonate
- Potassium carbonate
- Sodium carbonate
- Manganese oxide
The good news is that it isn’t a hazard. Efflorescence is simply salt and can easily be removed with the right cleaning products and techniques. What you should be concerned about is that it signifies a moisture problem in your foundation. In this blog, the team at Van Matre Construction will explain how efflorescence forms and how to treat, prevent, and remove it.
What Causes Efflorescence?
Different conditions can create efflorescence.
- When water infiltrates your basement wall, it dissolves water-soluble salts. As the moisture evaporates from the wall surface, it leaves mineral deposits that cause efflorescence crystals to grow.
- Efflorescence crystals may be caused by salt-laden soils or contaminated water used to create the wall concrete, mortar, or grout.
- Natural clays used to manufacture bricks frequently contain alkali sulfates. Although most fired clay bricks today have added chemicals to render these sulfates insoluble, any defects in the production process could create a future efflorescence problem.
In cooler climates, freeze-thaw cycles can accelerate the process. Humidity can also affect the appearance of soluble salts.
In many cases efflorescence is just an eyesore, but if these crystals grow inside the wall, they can push from the inside out and cause spalling, which is when the surface pops out or peels away. Over time, crumbling and deterioration may result.
How to Treat Efflorescence
There are four common ways to remove efflorescence from foundation walls. They all work best when the weather is warm and dry.
Use a Stiff Brush
Stiff brushes can be used to sweep efflorescence away from smoother surfaces. Because it is dry and powdery, be sure to wear a dust mask while sweeping it away.
Apply a Water Rinse
On rougher surfaces, use a pressure washer or garden sprayer to dissolve efflorescence and wash it away. Pressure washers should have the widest-angle tip applied to avoid damaging the wall surface. You may have to re-rinse or brush with this method, as the water can bring more salt to the surface as the substrate dries.
Apply Diluted Vinegar
If you prefer not to use chemicals, diluted white vinegar does an effective job of clearing away efflorescence.
Use a Chemical Cleaner
Another commonly-used treatment is speciality chemical cleaners. Muriatic acid in a mild solution (usually one part acid to 12 parts water) is one of the conventional cleaners. It is applied as follows:
- Presoak the basement wall to reduce its natural porosity and limit how deep the cleaning solution can penetrate.
- Use several mild individual applications instead of one large and aggressive dose.
- After the cleaning solution has been supplied, all residual chemicals need to be thoroughly flushed away with clean water. This step is critical because most cleaning solutions are highly acidic and will erode the masonry if not cleaned away.
Efflorescence has traditionally been cleaned by sandblasting. While this treatment removes the buildup, the difficulty is that the abrasive also erodes the wall surface and the mortar joints, increasing the porous qualities of the masonry and making the wall absorb water more rapidly. Sandblasting should therefore be used with caution and a waterproof seal applied to the masonry afterward.
If the efflorescence returns after removal, it means that water is continuing to enter the wall. You should arrange for a thorough inspection from a foundation repair specialist who can recommend reinforcement and moisture prevention solutions.
How to Prevent Efflorescence
If your home is under construction, you can prevent a future efflorescence issue by using quality materials and isolating them from salt and water sources. For example:
- Store all masonry materials off the ground and protect them with waterproof sheeting
- Incorporate protective structures like eaves, flashing, and overhangs into the building plans to reduce the risk of water getting into your walls from above.
- Make sure that your landscaping plans include runoff areas that draw water away from the foundation.
- Use vapor barrier sheeting between masonry and the ground. This will prevent water from getting in and salt from being absorbed.
- Use dense mortar joints and mechanical vibration to decrease porosity in the grout and slow down any ingress of water and salts.
- Use grout admixtures designed to reduce water content and porosity.
- After mortar tooling and final clean-up, apply a hydrophobic sealer to prevent absorption of water from rain and snow.
- When you’re installing pavers, make sure that bedding material and grading support adequate drainage. Permeable geotextiles can stop salt from being absorbed from the ground.
If you’re having an efflorescence issue with an existing home, you should:
- Set up water sprinklers so that they don’t direct water at your foundation wall
- Confirm that any surface and French drains are not clogged
- Arrange for a foundation inspection
The best to prevent efflorescence is to prevent moisture from entering your wall in the first place. If you see those white crystals, it typically means that you have a leak somewhere. Once the source of the water ingress has been found and remedied, your foundation walls can be treated with an efflorescence remover.
Schedule a Foundation Inspection Today
It is important to remember that cleaning efflorescence away from your basement walls won’t solve the problem. Unless the moisture issue is addressed, it will reappear and gradually erode your foundation.
At Van Matre Construction, we respond to efflorescence problems by:
- Assessing your foundation for cracks and other defects
- Examining the location of the build-up
- Reviewing building construction components like flashing details, roof and wall juncture, and wall sections for any possible moisture travel paths
- Checking for all possible water sources, including faulty drains, leaky pipes, and wall condensation
Depending on what we find, we may recommend drain installation to deal with oversaturated soil, foundation restoration, or crawl space repair and encapsulation. Our ultimate goal will be to stop any leaking, repair damage that could affect your foundation integrity, and prevent efflorescence from recurring. To schedule a free, no-obligation estimate, please call 303-668-2222 or contact us online.