Ice Effects: How Cold Affects Concrete Foundations
If you live a cold climate with freezing temperatures, cold weather can have a major impact on your concrete foundation. When the ground freezes and melts, it causes the soil to heave and contract. This is called the frost heave cycle. Ultimately, this cycle can have a major negative impact on your foundation because it causes instability in the soil.
Serious foundation problems caused by cold weather conditions and frost heave can be dangerous and expensive to repair. Unfortunately, foundation damage can occur even before the temperature reaches the freezing point. If the temperature falls below 40 degrees for three consecutive days, the likelihood of foundation damage is high.
How Frost Heave Damages Your Foundation
So what is frost heaving and why is it destructive? Frost heaving is caused by freezing temperatures that can damage structures in two ways.
- Cold temperatures cause ice to freeze beneath the concrete foundation producing frost heave. Frost heaving is the movement of the soil due to the formation of ice lenses. Ice lenses are long crystals formed by layers of ice within the ground.
- The other way is the ground collapsing which is caused by thawing ice lenses.
Both could affect structures causing vertical ground movement, shifting foundations, unlevel foundations, and cracks in the structure. Foundation walls, floors, footings, retaining walls, slab pavements and other structures can be seriously affected.
So how does frost heave work? In order for frost heave to occur, there must be freezing temperatures, water, and frost-susceptible soil. All three conditions must be present. The process involves the following steps:
- When the ground freezes, it starts from the top. Since the frozen area of the ground is much harder than the unfrozen area, it locks the foundation in place. As the ground continues to freeze, the freezing process progresses downwards causing the soil below to lift the top layers. This pulls the foundation up, creating gaps and spaces beneath the foundation.
- The ground beneath the foundation moves, filling the gaps and spaces that have opened up. The unfrozen area under the foundation eventually freezes.
- As the weather warms up, the ground thaws causing the foundation to come back down. Because the space under the foundation is partially filled, it doesn't go back down to its original position.
How To Prevent Frost Heave
Frost heave is an act of nature, therefore it cannot be totally eradicated. However, it can be prevented. Frost heaving mainly occurs in low-lying areas in the ground where there are depressions or dips. In order to prevent frost heaving, reduce the amount of water in the soil to prevent freezing from occurring by combining the soil with compost. Also, apply mulch into the soil to help regulate the temperature in the ground. There are also other methods of preventing heaving such as:
- Driving the footing deep into the soil
- Create a 'bell' shaped fitting at the bottom of the footing to prevent the soil from moving the footing
- Install reinforcing steel in the middle of the concrete slab
There are a variety of methods used by foundation contractors. Find the best preventative method for your property to eliminate the effects of frost heave. If you have visible damage caused by frost heaving in your concrete foundation, contact a foundation repair professional to assess your damages. They will determine the cause and provide the best repair method for the situation.