How Does Frost Affect A Foundation
Living in Northwest Ohio means living through the changing of the seasons. We think the changing seasons are one of the best things about this area! But, having four seasons also means dealing with severe temperature swings – from super hot to freezing cold. So, how does frost affect a foundation? People can adapt by dressing for these changes. Buildings and permanent structures can’t though. Your house is built with a foundation buried underground in soil that is porous, like a sponge. In the summer, dry weather can result shrinkage of the soil. In the winter, water trapped in the soil can freeze. That water expands when it freezes so the soil expands, too. These constant cycles of expanding and contracting is the cause of foundation failure. Here’s how frost affects a foundation.
When the Ground Freezes
With the exception of extremely dry conditions, most soil is going to hold moisture. In the winter, snow falls, melts and soaks the soil. It gets cold at night and the ground freezes. The soil around your house freezes at the top first. As the cold continues, the ground continues to freeze deeper and deeper. As the ground freezes below layers that are already frozen, the expanding water pushes upward, resulting in what is called frost heave. This condition is usually seen on sidewalks, driveways and patios first. As time goes on, this up and down motion can create cracks or settling.
These affected areas then need to be lifted to become level again. But soil doesn’t always lift upward. If confined, it will also expand side to side, putting pressure on the foundation. In cold areas, building codes require the foundation to be installed below the typical frost line for that region. Most foundations are required to be at least 36” below grade but the deeper the better. Older homes built on shallow crawl spaces commonly have foundation problems as a result of freezing ground.
Years or decades of soil expanding into a foundation will have an impact on the structural integrity of the concrete. In concrete walls, cracks form as the wall is pushed beyond its limits. Water then enters the home if the crack is wide enough.
A common DIY repair is to put epoxy, cement or spray on the crack. Although this may seem to be a good fix, water is still entering the crack from outside and, when it gets cold, freezes inside the wall. Now the small crack is working on becoming a larger crack. Crack repairs need to be done correctly by injecting them with polyurethane. This prevents water from entering the crack altogether.
Another common problem is when pipes are drilled through the wall to get to an addition, lamp post or garage. Freezing ground is working on these pipes, up and down, weakening them until they fail to seal at the wall or even allowing water to enter the pipe. As we all know, water and electricity don’t mix and it could create a very hazardous condition. It can also happen to water, gas and sewer lines. Sealing inside and out of these pipes is a must!
What can I do?
Once your foundation has damage, it should to be repaired sooner, rather than later. Cracks need to be properly fixed but it takes a trained eye to see the story the foundation is telling. To help keep this damage from happening, preventative steps can be made to help your foundation. Water management is key to a foundation’s health. Moving downspout water away from the foundation by using underground downspout extensions. Take a close look at the grade around your house. Are there areas of ponding water than can be re-graded to direct water away? Can yard drainage be installed to help move water to a better location? Even installing mulch can help give the ground a bit of a blanket to reduce how much frost develops.