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Efflorescence

Find out everything you need to know about efflorescence including what it is, what causes it, and how to remove and prevent it.

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Efflorescence is a fact of life with most types of concrete and masonry surfaces. It can be frustrating when these unsightly deposits make an appearance on your floors or walls. The good news is that efflorescence can be treated, removed, and prevented from reoccurring in the future. Keep reading to learn more about efflorescence. 

What Is Efflorescence? 

efflorescence chalky powder in basement

Efflorescence is a white, powdery substance that seems to appear out of nowhere on walls and floors made from brick, concrete, masonry, or stone. 

The crystallized salt deposits form when soluble salts make their way to the surface through capillary voids as a result of condensation, too much water in the mix, temperature changes, rain, dew, and moisture migration. 

When it hits the surface, the moisture evaporates and leaves deposits behind. The efflorescence can build up and leave ugly white patches or completely cover the concrete if it’s not addressed. 

Causes of Efflorescence 

For efflorescence to occur, there has to be water movement. Unfortunately, many contractors encourage the process when they introduce too much water into the concrete mix. Other sources of moisture include: 

  • Existence of voids in the brickwork resulting from bad workmanship 
  • Trees and small plants near the wall 
  • Leakage of rainwater and wastewater pipes, sanitary installations, and/or roof leakage 
  • Failure or non-existence of a damp-proof course 
  • Porous render attracting moisture from the outside 
  • Cracks in the rendering or deep in the brickwork 

Salts must also be present for efflorescence to occur. The most common types of salts in efflorescence include calcium sulfate (affects bricks), sodium sulfate (often seen in concrete-brick reactions), potassium sulfate, calcium carbonate, potassium carbonate, sodium carbonate, and manganese oxide. 

External factors like low temperatures, dew, groundwater, moist conditions, and condensation contribute to efflorescence. The frequency and intensity of efflorescence change depending on where you are in the country due to variations in water, snow, and rain. 

How to Remove Efflorescence 

The first thing you should do before removing efflorescence is determine its cause and mitigate it. It’s also crucial that you complete this task when the weather is warm and dry. That said, there are a few options at your disposal for efflorescence removal. 

Pressurized water: It dissolves the efflorescence quickly and effectively. However, the water must be dried off completely to prevent reoccurrence. You can use an air jet or wet vacuum to remove any standing water. 

Mild acid application: Applying a coat of vinegar, citric acid, or muriatic acid to the affected area can help dislodge the salt deposits where pressurized water fails. You may need to apply baking soda or a similar product to balance the acidity when getting rid of efflorescence from concrete. 

Brushing: Scrubbing the efflorescence using a brush is another way to dislodge the salt deposits from your walls. 

How to Prevent Efflorescence 

Here are six things you can do to control the upward movement of soluble salts:  

  • Architectural Adjustments 

Using eaves, overhangs, and a guttering system can also help keep water from infiltrating your foundation and its walls. 

  • Surface Sealer 

Another thing you can do is to apply hydrophobic sealer to the walls. What this does is prevent moisture from rain or snow from infiltrating the walls. Many sealants and paints are temporary solutions, however, and can flake off over time. 

  • Capillary Break 

Ask your waterproofing professional to apply a vapor barrier on the basement walls or in your crawl space to deter moisture and salt absorption. 

  • Regrade the Landscape 

Landscaping adjustments will ensure adequate runoff so water gets directed away from the house. You can grade the yard away and move away any flower bed that needs regular watering. If you normally use a sprinkler system, make sure it doesn’t spatter water to the exterior walls. 

  • Grout Admixtures 

Another effective way of preventing efflorescence is using admixtures to enhance grout floor. This method lowers water content and porosity, and in turn, prevents salt absorption. 

Waterproofing Can Help 

Efflorescence occurs naturally on concrete. Part of the problem is poor waterproofing. At Tar Heel Basement Systems, we offer a variety of basement, crawl space, and foundation waterproofing solutions to protect your property from efflorescence. Contact us today to request a free waterproofing inspection and repair quote

Our Service Areas

GREENSBORO / WINSTON-SALEM / HIGH POINT AREA

2910 Griffith Rd
Winston-Salem, NC 27103
336-283-2984

RALEIGH / DURHAM / CHAPEL HILL AREA

3333 Air Park Road
Fuquay-Varina, NC 27526

984-255-7529