Expansive soils create foundation damage. Expansive soils, including, clay soil, shrink-swell, and heavable soil, are all different names for the same thing.
Expansive soils are responsible for more damage to buildings than any other natural hazard.

This type of soil contains minerals like smectite clays, which absorb a lot of moisture. As the expansive soil soaks up water it expands – up to 15 times its dry volume. Furthermore, the expanded soil then pushes against your foundation and creates cracks or waterproofing problems.
In fact, as the expansive soil dries, it shrinks. The soil shrinkage gives your foundation room to move around. Consequently, this extra room removes the support from your foundation and will cause cracks, settling, and other foundation damage.
The pressure of expansive soils against your foundation can exceed 30,000 pounds per square foot.
Expansive Soil FAQ
If you’re not sure how expansive soil affects your foundation, read answers to what others have asked.
Your foundation is more sensitive to damage than you might think. Should you leave it unprotected, you may find yourself facing problems such as:
- Foundation cracks. Hydrostatic pressure around your foundation can cause the materials therein to rapidly expand and contract. To keep up with those changes, your foundation may crack, causing your HVAC unit to work less effectively and generally disrupting the overall structural integrity of your home. While you can live safely in a home with a cracked foundation, leaving the foundation with its crack in place can cost you more money in the long run than it might to invest in an immediate fix.
- Foundation leaks. A cracked foundation doesn’t always leak, but foundation leaks can often be traced back to foundation cracks. If you do not work to repair a broken foundation before a significant amount of rain or snow, you may find yourself contending with interior water damage on top of the damage done to your foundation.
- Foundation settling. If your foundation cracks on one side but not the other, it may begin to settle or otherwise sink into the ground, as its structural supports won’t be able to hold up its weight.
- Foundation bowing. In a similar vein, a damaged foundation can cause your home’s flooring to sag and walls to bow, leaving the floor weakened and often unsafe to walk on.
If you find yourself concerned about what kind of damage might befall your foundation, you can work with a professional contractor in your area to determine what the current state of your foundation may be. A thorough foundation inspection can help you better understand whether or not your home may already be suffering from damage. If it is, you can discuss potential fixes right off the bat. If it is not, you can instead discuss what preventative measures may best help you protect your space.
The term “expansive soil” describes clay as a broader category of soil. These soils react to the presence of water differently than silt or looser soils due primarily to their structure. The soil molecules beneath your home, for example, are both closely packed together and paired in the earth alongside a broad collection of minerals. These minerals, including but not limited to smectite clays, absorb water at a far more rapid rate than their cousins. If there are sulfate salts present in the soil, as well, then changes in temperature can just as readily cause your soil to expand. Partner rising temperatures with rain, and you may find yourself contending with unexpected and dangerous soil expansion beneath your home.
The good news is that no two expansive soils have the same mineral to soil ratio. You may not necessarily live in a location where your clay is partnered with both sulfate salts and smectite clays. If you’re not sure what kind of composition you’re living on top of, though, it may be worthwhile to check. You can reach out to area professionals for a soil assessment at your leisure. If you find that you’re contending not only with tightly packed clay but with a composition like the one referenced above, then you may be able to trace some of the problems with your foundation back to your soil. In turn, the professionals you come out to your property can equip you with waterproofing measures and repairs that keep expansive soils in mind.
The majority of foundation damage is caused by structural exposure to hydrostatic pressure. If you’re looking for ways to keep that excess water away from your home, it is in your best interest to:
- Invest in annual home inspections. While you can look over your basement or crawl space on your own, it may be to your benefit to reach out for professional guidance. The contractors in your area can walk you through annual inspections and let you know if it appears that anything may be amiss in your home.
- Grade your land. One of the simplest ways to protect your home from unwanted water runoff is to check the grade of your land and rework it, if necessary. Your land’s grade can either be positive or negative. Homes with a positive grade drive water away from their perimeters, whereas homes with a negative grade draw water in toward sensitive support structures. If you believe that your home has a negative grade, you can work with professionals to add an inch or two to the soil surrounding your immediate perimeter.
- Monitor your sprinklers. If you have sprinklers in your yard, you’ll want to use them on a regular basis, as a well-watered lawn is a lawn that’s not likely to let water run straight towards your foundation. That said, you’ll want to keep a wary eye out for leaks, as damage to your sprinkler or interior plumbing can cause you long-term problems in the future.
- Clean your gutters and downspouts. Your gutters and downspouts work in tandem to drive water away from your home. If you leave your gutters clogged, rain and snow runoff can fall straight down to your home’s perimeter, where it can, in turn, damage your foundation. It is in your best interest to regularly clear out your gutters, especially as the leaves start to fall in autumn.
- Waterproof your foundation before damage settles in. It is always in your best interest to invest in home waterproofing measures. You can speak with a contractor in your area about what foundation repair or waterproofing solutions—from sump pumps to piering—may best help keep your foundation in one place.
If you believe you’re experiencing a problem with your foundation, don’t hesitate to reach out to a professional contractor in your area.
The Experts at JES can Help!
If you’re not sure of the source of your foundation problem, give us a call at 757-301-4820, and schedule a free inspection. We’ll find out the cause of the problem and help you find the perfect solution.
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