Foundation cracks: when to worry

The best way to ensure a crack in your foundation doesn’t threaten the structural integrity of your home is to consult an expert. However, some general guidelines can help you determine if you have a serious problem.

Hairline cracks
Concrete shrinks slightly as it cures, and hairline cracks (about the width of sewing thread) are a normal result of it settling. They pose no structural threat and tend to appear within a year of construction. However, you should take steps to patch them.

Narrow cracks
Vertical or diagonal cracks that can’t be classified as hairline but are no wider than 1/4 of an inch are unlikely to be a serious problem. However, this is only the case if the cracks are stable and aren’t continuing to expand. Thin cracks can be filled with grout, and slightly wider ones should be filled with a caulk that’s compatible with concrete.

Wide cracks
Any crack that’s wider than 1/2 an inch should be inspected by a professional. In particular, those with a bulge may indicate structural problems. Additionally, a crack in your foundation that’s horizontal rather than vertical or diagonal presents more of a risk.

If you have wide cracks, horizontal cracks, or cracks that are getting worse, be sure to call a foundation contractor or structural engineer.