Thursday, February 4th, 2021 by Amanda Waldmann
Every year around this time, I write a little explainer about frost heave and how it affects your home’s foundation. With some wildly variable weather in the forecast over the next few weeks, this year is no different. So, let’s talk about it. What exactly is frost heave and how does it affect your home?
Frost heave is basically what it sounds like - soil shifting or “heaving” in response to frost, or moisture content. Think about when you toss a water bottle into the freezer to get it cold faster, and then forget about it. When you discover it, it’s swollen because the ice takes up more space than the water. Frost heave is the same process, but within soil. It’s very common and not anything that can be stopped, but can still cause issues for anything surrounded by that moving soil. Like your foundation.
Like I said above - when water turns to ice it expands. This expansion moves the soil to make room, and like most of nature, the soil follows the path of least resistance. If the expanding soil is surrounding your foundation, the concrete might be that path; concrete doesn’t seem like a low-resistance material but compared to the earth’s natural forces? It’s nothing.
So soil presses on on the foundation, and can force walls to shift (especially if they’re already weakened in any way). This can also cause wall cracks.
When temperatures rise a little and the frost melts, soil sinks back into place. This leaves gaps around the walls it had shifted; resulting wall cracks can also provide a path for water to move through the wall, which further weakens it for the next cycle.
Confused? Just think of the way waves lap at the sand, advancing and retreating, but the waves are ice and the sand is your house. Not great.
What to Do
Unfortunately, there isn’t anything you can do to flat out stop frost heave (unless you can manipulate the laws of science). What you CAN do to protect your home is to be observant.
Starting this month, every time there’s a major temperature change, go check your basement walls. Look for cracks and signs of water (either active leaks or stains from previous incoming water). If you have block walls, look for efflorescence - a powdery white residue that occurs when water dissolves minerals within the blocks then leaves them on the surface when it evaporates.
If you do see signs of cracks or wall movement, the best thing you can do is call us. While we can’t stop the soil from doing what it wants to do, we can stabilize your walls against future movement and protect your home. Questions? Call today.