Some foundation cracks are normal, especially small cracks that form as concrete cures and shrinks. Other cracks can be a sign of movement or a larger problem, and the only reliable way to tell the difference is to look at the crack in context, often with professional help.
Finding a crack in a foundation wall or slab can be unsettling. The good news is that many cracks are not cause for alarm. The goal is to know which ones deserve attention and what to do next.
Why Concrete Foundations Crack
Concrete loses moisture as it cures, and that causes it to shrink slightly. Shrinkage often leaves thin cracks in walls and slabs, sometimes within the first year after construction. Temperature changes add expansion and contraction over time.
Other cracks are caused by forces outside the concrete. Soil that settles, swells, washes out or pushes against a wall can stress a foundation. Water is often involved, since it changes how soil behaves.
Cracks That Are Often Less Concerning
Many homeowners see thin, fairly straight cracks that don’t change over time. When the two sides of the crack stay level with each other and there are no other signs of movement, these are commonly related to shrinkage. They may still let in moisture, so sealing them can be worthwhile.
Even so, appearance alone does not prove that a crack is harmless. An article can’t tell you whether a specific crack in your home is safe.
Signs That Call for a Closer Look
Some patterns suggest the foundation may be moving or under stress:
- cracks that are getting wider or longer,
- one side of the crack sitting higher or farther out than the other,
- walls that bow, lean or bulge,
- stair-step cracks in block walls,
- water coming through cracks, or
- sticking doors and windows, uneven floors or new drywall cracks upstairs.
Any of these signs is a reason to arrange a professional evaluation rather than wait and guess.
What to Do If You Find a Crack
Start by documenting it. Take dated photos, and mark the ends of the crack with a pencil so you can tell if it grows. Note whether water comes through after rain.
Check outside the house too. Gutters that overflow, downspouts that empty against the wall and soil that slopes toward the foundation can all contribute to foundation issues. North Carolina’s heavy rains make drainage worth checking around any home. Our article on moisture under concrete slabs explains how ground moisture affects slabs inside homes.
Avoid digging next to the foundation or trying structural repairs yourself. Foundation work can affect the stability of the house and should be handled by qualified professionals.
Our concrete foundation repair page explains how foundation concerns are evaluated before any repair is recommended. If you’ve found cracks in a foundation at your Burlington home, we can help you understand what you’re seeing and what next steps may make sense.
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