If you have a concrete wall, air pockets could also be a reason for cracks.
“Also known as ‘honeycombs,’ these air pockets are usually a result of poorly mixed concrete, which can form throughout your walls over time,” explains Chuck Naish, founder of City Residential Foundation Repair.
How severe are the cracks in the wall?
Once you’ve identified a crack in the wall, your next step is determining how bad the crack actually is.
“An isolated crack visible only from the inside of your basement or crawl space isn’t immediately a cause for alarm,” says Andy Beery, founder and CEO of Acculevel in Rossville, IN.
When the seasons change, there can be some expansion and contraction in a foundation, Beery explains. “This can lead to hairline or superthin cracks that are consistent in width.”
However, if you see multiple cracks, or there are cracks throughout your home, your foundation may be settling. Settling cracks are more concerning than hairline cracks, so you’ll want to determine which kind of cracks you have. Beery recommends the penny test.
“While holding the penny between your finger and thumb, press the edge against the crack,” he says. “If the crack is thinner than the penny, you have a hairline crack—but if it is wider than the penny, especially if it tapers and widens, this is a settling crack.”
Cracks around door frames, windows, and the ceiling can also indicate your foundation is settling. If you find cracks in these areas, Beery recommends another test.
“See if the door or window will open and close easily,” he says. “If it won’t stay open without your holding it, and it won’t stay closed unless you lock it, this is more evidence of settling.”
He recommends getting settling cracks repaired as soon as possible.
You might also notice cracks that look like stair steps in your basement or crawl space, or outside the house if you have a brick foundation. These types of cracks are common, but they do indicate problems in your foundation. If you notice stair-step cracks, it’s time to call a contractor to investigate.
Other more serious indications of foundation damage are large cracks, sloping floors, and separation between the walls and the ceiling, says Alex Berezowski, owner of the Foundation Experts.
Repairing cracks
If you have just a hairline crack, Cantor says you may be able to use mesh tape, dab mud over the cracks, and then repaint the area.
“If the foundation is cracking due to shrinkage, then sealants may be used to fix the problem,” says Berezowski. “This often includes using modified mortars/masonry repairs or epoxy to fill in the cracks.”
However, it’s probably best to call a foundation repair team, which can correctly assess the type of crack and the necessary materials to fix it.
“If the right material isn’t used, the repair will not last,” warns Naish.