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Clay Bowl Effect

The clay bowl effect is why water builds up in the foundation soil and exerts pressure on the walls. Learn what you can do to protect your home.

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We all know that earthquakes, floods, tree roots, and settlement all have the potential to damage your foundation. However, these aren’t the only culprits. The clay bowl effect is a force to be reckoned with and it can damage your foundation walls too. 

What is it, how does it happen, and what can homeowners do about it? Read on to find answers to these and other concerns you may have. 

Understanding the Clay Bowl Effect 

Typically, construction starts with ground excavation to make room for the foundation and basement or crawl space. Once the foundation is built, a concrete floor is poured. Some of the soil that’s been dug out is then used to fill the space around the edge of your foundation and basement or crawl space walls. 

The backfill soil is mostly loose and fluffy while the untouched soil close to it remains firm and stable. Anytime it rains, the backfill soil will absorb more water than the dense, hard-packed soil nearby. This creates a “clay bowl” around your home, one that holds water exactly where it’s not supposed to. 

If you notice one or more of these signs, you’re likely experiencing the clay bowl effect: 

  • Foundation cracks that leak water 
  • Higher relative humidity in the basement or crawl space than other sections of your home 
  • Increased radon levels 
  • Persistent mold problems 
  • Puddles on the floor 
  • Dark spots on your basement walls/floors 

Should You Worry About the Clay Bowl Effect? 

Absolutely. The clay bowl effect can damage your foundation walls and cause water to leak into your basement or crawl space. The problem could be much worse if you have porous concrete walls or floor wall joints. Gaps around pipes or wires and leaky basement windows can also make your home vulnerable to water. And then there’s the odorless radon gas that can build up in the basement without anyone noticing. 

You can expect serious structural damage to happen soon if you don’t mitigate the problem. As pressure mounts, your foundation walls may reach a breaking point where they’ll collapse as they can no longer hold out. This can be disastrous. 

Possible Solutions 

Bowing or leaning walls can be straightened using wall anchors. These systems help stabilize the walls, preventing further bowing. Your foundation contractor will embed them into the soil further away from the foundation. Wall anchors can be installed any time of the year. Installation is less disruptive, and the job can be done within a day, leaving you with strong walls that won’t tilt or bow any further. 

Another measure you can take is to install an exterior French drain – curtain drain. It’s placed along the exterior foundation to catch groundwater before it gets inside your house. While this system will slow down the rate of water infiltration, it can address the larger pool of damp soil on the foundation. 

If drainage issues persist, installing an interior drainage system in your basement or crawl space can help reduce pressure buildup and flooding. Any water that gets in through cracks gets channeled to a sump pump system, which ejects it. 

Waterproofing the foundation from the outside can also help stop groundwater from seeping into your basement or crawl space and getting your belongings wet.  The clay bowl effect doesn’t have to spell the end of your foundation. Complete Basement Systems can help you implement solutions that will stop the buildup of hydrostatic pressure so your foundation walls remain intact. If the walls have cracks or are bowed, we can seal those gaps and straighten them out using wall braces. Request a free foundation inspection and repair estimate today.