Crawl Space Efflorescence: What Is It and How Do You Deal With It?

Whenever it rains, and moisture starts infiltrating your crawl space, you may notice some white residue on the wall. This is efflorescence. It’s an indication that water or moisture is passing through concrete or masonry.

It appears when water-soluble minerals like calcium or lime crystallize on the walls or floor. The residue usually looks like a white chalky substance. 

Here, we are going to demystify efflorescence by showing you what causes it, what it’s telling us, and what you can do to stop its formation. 

Is Efflorescence Harmful? 

While efflorescence itself isn’t harmful, it is a warning sign of a water seepage issue that needs to be addressed. With time, water intrusion will lead to mold and mildew. When airborne, mold spores can trigger allergies and respiratory issues, particularly in individuals with sensitivities. Prolonged exposure to damp conditions can also lead to the growth of harmful bacteria, further compromising indoor air quality.

It’s possible to physically remove efflorescence from your crawl space walls? Yes, but this requires you to get into the crawl space and scrape the loose materials off the walls with a wire brush. This isn’t ideal, especially since you will have to perform this act over and over because you are not addressing the root issue, water intrusion.

Can a Dehumidifier Help Out? 

Actually, your dehumidifier has nothing to do with the chalky substance on your wall. If the crystals are forming due to exterior sources of moisture, a dehumidifier won’t stop the salt deposits from forming.

What you need to do is fix the underlying issues that lead to the formation of efflorescence. Once you fix the issues, you can get a dehumidifier and use it to control the moisture in the crawl space. Your crawl space health and dryness depend on it, especially in the summer months when humidity is high. 

The best way of stopping salt and mineral deposition is to reduce or prevent the inward movement of water. This requires installing interior drainage and possibly a sump pump.

Outside, ensure your gutters are flowing freely and your yard has a positive slope. This way, water won’t collect around or near the foundation.

Causes and Cures for Efflorescence 

Efflorescence can arise from a number of things. Here are the major causes: 

Site surface drainage 

During construction, it’s important for the builder to use a well-graded concrete mix with a water reducer. The concrete should also be properly consolidated and placed directly on a vapor retarder. These measures result in dense concrete slabs with low amounts of bleed water and fewer pores. Such a slab will resist water absorption and moisture movement. 

Wall cracks 

Cracks and crevices on the walls of your crawl space act as conduits for outside water. To fix this, your crawl space walls must be sealed and water must be drained using an interior drainage system, like the Crawl Space Drain, to help relieve hydrostatic pressure on the walls. 

Negative grading 

A negative slope allows water to flow back and pool around the foundation. This water may end up in the crawl space. To correct this problem, you will have to create a positive slope. Your landscaper can help you with this. Ideally, your yard should slope by six to eight inches over 10 feet so water flows out naturally. 

Excess moisture 

Moisture buildup often leads to condensation. The water beads that form when water vapor cools gets absorbed to the surface. When temperatures rise, the water vapor moves up and evaporates leaving behind salt or mineral deposits. To tame moisture, get an energy-efficient dehumidifier for the crawl space. It will dry out the moisture from the crawl space. This will prevent condensation and rust from forming on your tools, appliances, and metallic objects. 

Moisture or water from the ground 

Ground moisture and water can also contribute to condensation and wood rot in the crawl space. Encapsulation is the answer. Installing a high quality vapor barrier on the walls and floor seals out water and moisture, keeping the crawl space dry and free of efflorescence.

Get Professional Help

Whether you’re noticing efflorescence for the first time or it has been there for many years, you’ve got to deal with it fast. Otherwise, the water that’s bringing the salt deposits into your crawl space will wreak havoc on your home.

Take the first step uncover the real source of moisture and resolve it once and for all with Foundation Recovery Systems today. Our commitment to providing top-notch solutions, coupled with exceptional customer service, has earned us thousands of positive online reviews from satisfied homeowners.

With FRS, you can rest assured that your home is in the hands of experts dedicated to delivering quality products and ensuring your peace of mind. Contact us today for a free inspection.

FAQs

Is efflorescence more common in certain climates?

Yes, efflorescence is more common in climates with frequent rainfall, high humidity, or significant temperature fluctuations that can cause condensation.

Will efflorescence go away on its own? 

In some cases, efflorescence may disappear naturally over time due to weathering. However, if the underlying moisture issue remains unaddressed, efflorescence is likely to recur.  

How do I remove efflorescence? 

Efflorescence can often be removed by dry brushing followed by washing the surface with clean water. For more stubborn cases, a mild acid wash may be necessary. However, it’s crucial to treat the moisture problem for a lasting solution.  

Leah Leitow

Content Writer

Leah is a Content Writer for Groundworks with more than ten years of experience working in the foundation repair industry. Her experience ranges from working with homeowners to find the right solution to training inspectors and staff. In her background as a Michigan journalist, she gained invaluable insight into people's lives throughout our state. Leah lives in metro Detroit with her husband and two sons.