Cochren Foundation & Repairs have long worked with homes experiencing water infiltration and structural problems, including bowed basement walls and house settlement. In recent years, however, they have also faced a different kind of movement – homes and attached structures lifting upward due to frost. In just 5 days, 13 homes were found to have sustained frost-related damage ranging from minor movement to severe structural issues.
Most people have seen the effects of frost in southern Ontario, including crooked fence posts, leaning pillars, rough highways, crooked signs, and uneven sidewalks. What many homeowners do not realize is that frost can also cause parts of a home to lift upward due to a phenomenon known as frost adhesion.
What Is Frost Adhesion?
Ice lenses form in porous soil and grow by attracting groundwater. This movement of water is what drives lens growth and can lead to volume increases well beyond the normal 9% expansion that occurs when water freezes into ice.
Frost adhesion is a form of frost heave and typically occurs under the following conditions:
- Prolonged subzero temperatures
- Frost-susceptible soils
- An abundant source of water
How Frost Adhesion Damages Foundations
In our area, footings are typically buried 4’-0” below grade to prevent frost from moving beneath the foundation and lifting the home. With frost adhesion, however, the ice attaches to the side of the foundation wall and can form a bond strong enough to lift the structure upward.
Frost adhesion tends to affect lightweight, unheated structures such as cold cellars or garages with shallow foundations. Buildings with previously cracked foundation walls caused by settlement are particularly vulnerable.
The sudden appearance of a crack is often accompanied by a loud bang if someone happens to be nearby at the moment it occurs. Plain, unreinforced concrete is very brittle, and when its ultimate strength is exceeded, it can crack suddenly without warning – much like the sound of ice cracking on a frozen lake.
Distortion is caused by uneven lifting around the garage or cold cellar, which can make doors and windows difficult or impossible to operate. A 2” difference across the top of a doorway is not uncommon. Large step cracks may appear in the brick veneer, and concrete floors often heave and crack as the structure shifts.
What Happens in the Spring?
Good News
In some cases, the foundation may settle back down with the spring thaw. However, if soil falls into the cracks formed in the foundation wall during frost adhesion, the building may not be able to return to its original position, creating a much larger repair issue.
Repair and Prevention
Solution
If a home has moved due to frost adhesion this year or in a previous winter, it is likely to move again during future periods of prolonged cold unless the contributing conditions are addressed. For that reason, it should be dealt with as soon as possible.
The remedy for foundations affected by frost adhesion is to remove or reduce one of the three contributing conditions by:
- Removing excess water from the soil
- Removing frost-susceptible soil
- Insulating to prevent frost penetration
No two homes are the same. Finding a reliable and cost-effective solution creates a unique challenge in every case. The investigation should also consider whether the foundation had been previously damaged by house settlement. For this reason, each case should initially be assessed as both settlement-related and frost-related movement.
Concerned about frost heave or foundation movement? Call us today for an estimate: 519-647-0256.
Or submit your estimate request online.