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Homeowner’s Guide to Clay Soil & Foundation Damage

Pile of soil

Have you ever wondered why some houses seem to have more foundation problems than others? The answer often lies beneath your feet—in the soil.

Clay soil, also known as expansive soil, causes issues for many homes. Understanding how clay soil affects your home’s foundation can help you take steps to protect your property and avoid severe damage. Let’s dive in!

What Is Clay Soil? 

Clay soil is a type of soil that contains tiny particles. These particles are so small that they can pack together tightly, leaving little room for air. Because of this, clay soil absorbs a lot of water, causing the soil to expand.

On the other hand, when the soil dries out, it shrinks. This constant cycle of expanding and contracting can put a lot of stress on a home’s foundation.

This fine-grained natural soil comes in various colors, shapes, and structures. Sometimes, it is tricky to determine whether you have this type of soil in your yard.

Characteristics of Clay Soil:

  • High Water Absorption: Clay soil can hold a lot of water, swelling up like a sponge.
  • Sticky Texture: When wet, clay soil feels sticky and is difficult to work with.
  • Hard and Cracked: When dry, it becomes hard and may crack easily.

Where is Clay Soil Found?

Clay soils are most common in the South (although they can be found in pockets all over the country). Many homes in Alabama, Mississippi, Georgia, and Tennessee were built on this type of soil.

Homeowners with houses on expansive soils, like clay, need to take extra steps to keep their homes safe and stable. In the spring, heavy rains can make the soil swell up, and in the summer, the soil shrinks when it gets dry. This swelling and shrinking can cause serious damage to the foundation if not properly managed.

Clay Soil and Construction Risks

Excavator moving soil.

Clay soils can be a real challenge for builders. Constructing foundations, driveways, pools, slabs, or decks is difficult when clay soil is involved. However, with proper preparation, it is possible to create a stable base for construction.

One method is to excavate the clay soil and mix it with gravel, which makes it much more stable for building a foundation. Still, this doesn’t guarantee the stability of clay soil, so always be aware of the risks.

How Does Clay Soil Damage Foundations?


Clay soil.

When clay soil gets wet, it swells up. This can push against your foundation, causing it to crack or shift. The pressure from the expanding soil can lead to significant damage over time, as the constant force can weaken the structural integrity of your home.


Cracked, brittle soil.

As the soil dries out, it shrinks and cracks, which can create gaps under your foundation. These gaps can cause parts of your foundation to sink into the ground, leading to cracks and instability.

Uneven Moisture

Bricks cracking and becoming uneven.

Different areas of soil around your home may have varying moisture levels, leading to uneven expansion and contraction. This can make parts of your foundation settle unevenly, where one part of your home sinks more than another, creating stress and damage to the structure. 

How to Repair Foundation Damage

Repairing foundations built on clay soil requires special waterproofing and foundation repair solutions. It’s best to work with professionals (like AFS) to ensure the job is done correctly. Here are some of the repair methods we use:

Pier attached to foundation footing.
  • Foundation Push Piers: Galvanized steel piers reach stable soil below the foundation, providing support and potentially lifting the home back to its original position.
  • Foundation Helical Piers: Screwed into the ground to transfer the house’s weight to stable soil, ideal for lighter structures.
  • Steel I-Beams: Reinforce and stabilize basement walls pushed inward by expanding clay soil, preventing further movement.
  • Wall Anchors: Stabilize and strengthen walls that have bowed due to soil pressure by anchoring into stable soil and pulling the wall back into place.
  • Crawl Space Support Jacks: Stabilize and lift sagging floors in crawl spaces, preventing further settling and damage.
  • Slab Piers: Installed below concrete slabs to stabilize and lift them back to their original position, addressing settlement issues in slab foundations.

Additional Tips for Homeowners

  • Regular Inspections: Perform regular inspections of your home’s foundation and surrounding soil. Early detection can prevent more serious damage.
  • Planting Considerations: Be mindful of where you plant trees and shrubs. Their roots can affect soil moisture levels near your foundation.
  • Soil Testing: Have your soil tested to determine its composition. This can help you understand the specific challenges posed by your soil type.
  • Seasonal Maintenance: Adjust your maintenance routine based on the season. For example, in dry seasons, you may need to water the soil more frequently.

Prevent Foundation Damage With AFS

AFS crewman posing with shovel in front of work truck.

Clay soil can threaten your home’s foundation, but understanding and managing it can protect your property. Watch for signs of damage and act early to keep your home stable.

If you notice any issues, contact AFS Foundation & Waterproofing Specialists for a free inspection. Staying informed and proactive helps maintain a strong foundation, so don’t wait!

Clay Soil FAQs

You can determine if your home is built on clay soil by checking the soil’s texture and color, or by consulting local soil maps and reports. Clay soil is typically sticky when wet and hard when dry.

Yes, clay soil can cause issues with driveways, sidewalks, and other structures, leading to cracks and uneven surfaces due to soil movement.

Updating gutters and downspouts, planting trees and shrubs away from the foundation, and maintaining consistent soil moisture levels can help mitigate the damaging effects of clay soil.

Related Resources

Ted Dryce

Ted Dryce

Content Writer

Ted is an SEO Content Writer who has been with Groundworks since 2021. He’s covered home repair topics ranging from crawl space encapsulation to regional soil conditions. When he’s not working, Ted is performing improv comedy and working on his own creative projects.

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