Expansive Clay Soil and Your Home’s Foundation
/Depending on your location, your property may be full of expansive soils, a type of soil that fluctuates in size depending on the temperature. These fluctuations can lead to foundation movement and even damage to a home or building.
Here’s everything you should know about how expansive clay soil can affect your home’s foundation.
How Temperature Affects Expansive Clay Soils
In dry conditions, expansive soils shrink and crack, pulling away from a foundation wall and creating a gap. This gap fills with debris including stone, gravel, loose soil and more.
During wet conditions, expansive soils can increase in volume of 10 percent or more. This type of soil absorbs water rather than allowing it to pass through. The extra material that’s accumulated in the crack during the dry conditions increases pressure on the foundation wall, pushing the wall inward.
The constant cycle of shrinkage and swelling creates repeated stress on concrete foundations, causing foundation movement, cracks and damage. This occurs when the soil has not been properly prepared and the foundation/footings haven’t been sunk deep enough.
Basements can also suffer moisture problems from expansive clay soils since water can easily run off and seep through basement walls.
Soil expansion and shrinkage can be exacerbated due to certain landscaping around a foundation, such as certain trees that displace soil.
Signs of Soil Expansion and Shrinkage
Wondering if your concrete foundation has been damaged from expansive clay soil issues? Below are some common signs to look for:
Cracked or bowed concrete foundation walls
Cracks in plaster walls, especially in corners
Sticking doors and windows
Cracked or separated brick veneer, concrete driveway or garage
Soil pulling away from foundation walls
Wet basements
The best way to know is by contacting a foundation expert.
How to Protect Your Home’s Foundation from Expansive Clay Soils
Not sure if you have expansive soils on your property? (As discussed in Report #32 of the Ontario Soil Survey, much of Wentworth County is covered by clay and there is an extensive clay plain called the Haldimand Clay Plain above the escarpment that covers Saltfleet, Binbrook, Glanford and part of Ancaster).
A testing lab can analyze your soil to identify its expansive properties. If the moisture content can be stabilized, the expansive soils normally will not cause foundation problems.
To maintain a constant moisture level in an existing home, install foundation landscaping or water the soil around the foundation during dry periods. Doing so helps stabilize future foundation movement.
In new construction, soil problems can be avoided by pre-wetting the soil before placing the foundation.
How to Repair Foundation Damage Caused by Expansive Clay Soil
Whenever foundation damage has occurred, a foundation repair contractor should be consulted as soon as possible.
After completing a thorough inspection, a foundation expert will stabilize the soil and connect the foundation to a more solid, deeper soil. Any waterproofing, cracks, or damaged walls will be repaired. Proper drainage is also key to preventing foundation damage, so the proper functioning of gutters, downspouts and more will be verified.
The fact that expansive soils can damage a material like concrete is a true testament to the destructiveness of the material. Let us help you prevent or repair foundation damage caused by expansive clay soil. If you have a leaky basement, contact our foundation experts today for more information.
