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What You Need to Know About Expansive Soils

Expansive soils can cause problems when they absorb water. Find out what you can do to avert foundational issues that can cause structural problems.

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Many homeowners don’t consider the soil under the home as a threat to the health and stability of their foundation. Believe it or not, expansive soils are the leading geologic hazard in the U.S. While not as severe as earthquakes, they’re responsible for more financial loss than other natural hazards and disasters. 

Most of the foundation problems you’re likely to face in Appomattox, VA, are due to these types of soils. Let’s get started with the basics of expansive soils and look at the possible fixes. 


What Are Expansive Soils?

These are clayey soils that contain water-absorbing minerals. These soils tend to shrink or swell, depending on the moisture content. When it rains, expansive soils swell in volume. And they can expand by up to 10%. They will keep swelling until they reach their saturation point. 

Most expansive soils have one or more of these minerals: 

  • Beidellite 
  • Attapulgite 
  • Sulfate salts 
  • Vermiculite 
  • Bentonite 
  • Chlorite 
  • Nontronite 

How much they swell depends on the dry intensity, stratum thickness, and degree of soil saturation. The initial moisture content and ground load also determine their swelling potential. 

What Problems Arise When the Soil Swells? 

Expansive soils swell whenever they absorb moisture, and then they will exert pressure on your structure. The outward force can cause structural problems like cracks on walls and floors. Cracks and openings around the foundation allow water to enter your basement. Water buildup will cause wood rot and mold growth, among other issues. During summer, these soils give up their water and shrink. When this happens, they crumble under the weight of your home. This is what causes deformations and foundation settlement. 

What Are the Signs of Swelling Soils? 

Clayey or swelling soils will always trigger foundation or structural issues due to swell and shrink cycles. The main ones are: 

Best Fixes for Expansive Soils 

Let’s look at the common ways of stabilizing expansive soils. 

Lime treatment

Injecting hydrated lime into expansive soils helps reduce the plasticity and swelling capacity of the soil.  

Cement treatment

You can also use cement to treat and stabilize clay soils. Cement lowers the saturation limit and the plasticity of swelling soils and increases their strength. 

Chemical Injection

The other option is injecting the soil with water to pre-swell it, then adding a stabilizing chemical fluid. 

Foundation reinforcements

It’s great for stabilizing and restoring a sunken foundation. Various piering systems are available. Talk to your foundation repair contractor to see what option works for you and your home’s unique repair needs. 

Moisture control

The same contractor can install various waterproofing measures to control moisture and stop water seepage around your home, such as a vapor barrier, interior drainage, or a dehumidifier. 


Grade your yard to reduce the amount of water that gets into the swelling soil and you will keep their swelling potential down. Pay attention to your landscaping efforts by removing all flowers or garden plants that are less than five feet from the foundation wall. Do the same for trees that stand less than 20 feet away. Such trees absorb a lot of water in summer, and this can lower the moisture content of the soil. 

Watering the Soil

Try to keep the soil most in summer by watering the ground on hot days. By maintaining the moisture content, you will prevent the swell and shrink cycles that are responsible for foundation settlement. 

Reinforced Slab-on-grade

Are you constructing a home on clayey soils? Create a strong foundation that isolates your home from the expansive soils. Installing a reinforced slab-on-grade with underlying crossbeams helps minimize soil shifts. 

Expansive soils can cause serious and costly damages to your home. Before you build a house, find out what type of soil you’re working with. Also, make sure the builder prepares the foundation and soil properly. 

Protect Your Foundation 

Don’t agonize over what expansive soils might do to your home. If you suspect there’s a problem with the soil beneath your foundation, get in touch with JES Foundation Repair for a free foundation inspection and repair quote. We will assess the situation and tell whether there’s cause for alarm or not. Our foundation experts have been stabilizing shaky foundations for years and know the best solutions that will help keep your home safe and sturdy.

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