Last winter in Ottawa, many of us heard the term frost quake for the first time. Foundation cracks can occur due to this phenomenon. The cause is water draining into the ground, expanding as it freezes. This puts stress on its surroundings including foundations. Early season snowfall, before prolonged low temperatures, reduces the risk. Snow is a great insulator. The more snow the less frost penetrates the ground. We as Ottawa concrete contractors, perform foundation repair and crack injection all winter long. The fact is that snow insulation and heat lost through the basement walls, allows us to do so efficiently. You would need a jackhammer to dig down 5 feet in an open area without snow coverage (frost line). Block foundation walls are particularly vulnerable to frost action. Lateral pressure can push on the block wall. This can cause horizontal foundation cracks that run the length of the wall. This effect is more pronounced on walls bordered by asphalt driveways. Snow is removed (driveway) eliminating the insulating benefit. These foundation cracks can have a profound effect on the structural integrity of the house. The costs to repair these situations can rise exponentially if left untreated. Interior repairs with steel or carbon fibre reinforcement can be used. This is often done in conjunction with exterior excavation. The material is hauled away and replaced with free-draining stone aggregate after repairs and waterproofing. This is a job for a concrete repair contractor.
Tips to help reduce costly horizontal foundation cracks
- Check the wall on the inside, if it is uncovered, a foot or so below the outside ground level (horizontal crack).
- Check on the outside for inward bowing.
- Call a foundation crack specialist for advice and/or estimate.
- Most driveways are wide enough to leave or even bank snow (insulator).
This winter has been very good for us so far. Temperatures are much higher on average compared to last year. Things change, be prepared.