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Will a Dehumidifier Stop Efflorescence in my Crawl Space?

During the wet season, heavy rain makes it more likely for water to get into your crawl space. One of the most common side effects of crawl space water is efflorescence.

Although this white, powdery substance is not harmful in and of itself, it is a clear sign of too much moisture in your crawl space. Failing to fix this issue may lead to more extensive water damage in your crawl space—but a dehumidifier can help.

What is Efflorescence? 

Efflorescence is a white, chalky substance that generally forms on walls with porous materials like brick or concrete. It is not a harmful material but it is often mistaken for mold growth.

Efflorescence is really just mineral deposits left over from a chemical reaction that takes place when water-soluble materials (like calcium and lime) mix with moisture. When water or moisture is absorbed into concrete or masonry walls, it triggers this reaction.

The minerals move with the water toward the surface of the walls through capillary voids (tiny gaps in the building materials). When these minerals dry out, crystals form and leave behind the substance we call efflorescence.  

What Causes Efflorescence? 

There are three components needed for efflorescence to occur. 

  • Water-soluble salts: The walls on which efflorescence forms need to have some water-soluble salts. Brick, cement, and concrete walls contain large amounts of limestone, sand, or clay, which contain large amounts of minerals, including salt. 
  • Water or moisture: Efflorescence requires moisture or water to come into contact with the salt to dissolve it. So when you see efflorescence in your crawl space walls, this is a sign of water intrusion. This water can be from a plumbing leak, flood, poor grading, groundwater, or heavy rain.  
  • An entry point like porous concrete or cement: The water needs an entry point to enter your crawl space. Wall cracks, pores in the concrete, and even gaps in floor-wall joints can create entry points for water.  

How Does a Dehumidifier Prevent Efflorescence?

Installing a dehumidifier in your crawl space will help prevent efflorescence from appearing.  Dehumidifiers remove excess moisture from the air in your crawl space. By doing so, it makes the area (and everything within it) drier. Efflorescence can only occur when moisture mixes with soluble salts found in common building materials.

When you remove the moisture in your crawl space, you make it nearly impossible for efflorescence to appear. Keep in mind, a dehumidifier alone may not solve the problem completely. It’s best to use other water management systems alongside the dehumidifier to provide protection from all forms of moisture.

Other Ways of Dealing with Efflorescence in the Crawl Space 

To stop the formation of efflorescence, you need to stop the movement of water into your crawl space. Otherwise, the efflorescence will come back over and over again unless you fix it at the source. Plus, if you don’t fix your water issues, you could open yourself up to more problems in the future. Even small water leaks can lead to severe water damage, floods, or cracked walls, which can cause much bigger and costlier problems.  

  • Add Drainage: An effective way to quickly remove water from your crawl space is with improved the drainage. The best forms of drainage include sump pumps and crawl space drains. Both of these tools capture groundwater and move it away from your home. This makes it much harder for water to pool below your home and seep into the crawl space walls.
  • Install a Vapor Barrier: Vapor barriers prevent humid air from being absorbed by walls in your crawl space. This extra layer of protection will keep the walls dry, even on the most humid days. We advise staying away from store-bought vapor barriers, as they are often too thin and flimsy to offer any lasting protection. Instead, work with a professional team like Innovative Basement Authority to install a durable, mold-resistant vapor barrier.
  • Fix wall cracks: Cracks on your foundation walls make it easy for water and moisture to seep in through your porous walls. Once you realize cracks or gaps on your masonry walls, you need to seal them to prevent moisture from seeping in. Consider patching up the affected areas from the outside using an elastomeric coating that can keep up with the constant expansion and contraction of your foundation walls. 

Schedule a Free Crawl Space Inspection With Innovative Basement Authority

If you notice efflorescence in your crawl space, don’t wait—the problem will only get worse. As part of our crawl space repair and encapsulation process, we install an energy-efficient dehumidifier to help eliminate moisture in your crawl space. Contact us to schedule a free crawl space inspection with our expert team today. 

Leah Leitow

Leah Leitow

Content Writer

Leah is a Content Writer for Groundworks with nearly 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.

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