What Is the Freeze-thaw Effect?

The freeze-thaw effect refers to the cycle that liquid goes through when it freezes and then thaws. The reason you should worry about the freeze-thaw effect as a homeowner is because of what it can do to your crawl space, basement, and concrete slabs. When liquid freezes into ice, it expands by about 9%. It may not seem like it, but expanding ice has the ability to tear through concrete and displace soil.

During the winter, as the snow falls and melts throughout the days, the soil under your concrete gets saturated with water. When it’s time for that moisture to freeze, the expanding ice displaces the soil only to leave gaps once it melts. These gaps loosen up the soil and cause concrete settling, which is why you might notice that your concrete feels a bit wobbly after a long winter. It doesn’t help that the freeze-thaw cycle also creates micro-tears in the concrete, thus making it more porous and allowing more moisture to reach the soil. If you’re not careful, the freeze-thaw effect can debilitate your concrete to the point where it cracks under the slightest hint of weight.

That soil displacement also happens around your foundation. The soil right around it is already incredibly porous due to the way it was filled in when the foundation was built, but with the freeze-thaw cycle, the clay bowl effect will only be amplified. By the time spring comes around and all the moisture from the soil melts, the hydrostatic pressure will be in full effect. A proper foundation drainage solution is the only way to minimize the damage caused by the freeze-thaw effect. The less groundwater surrounding the foundation, the less water damage will take place.