Basement Floor Cracks? Here's What to Do

Have you recently noticed cracking in your basement concrete flooring?

There are two main causes of basement cracks: shrinkage and settlement. Before you panic, know that concrete basements will always crack – and that usually, it rarely results in structural problems.

Here’s how to know whether your basement cracks are cause to worry over and what you should do about them.

Shrinkage and Basement Floor Cracks

When basement concrete cures and becomes solid, a range of shrinkage will occur. Cracks form when temperatures drop or rise quickly, affecting the speed of the curing process. Shrinkage also happens as a home naturally ages. Typically not indicative of a structural problem, these types of cracks can be sealed using an elastomeric caulking product created for use on interior masonry.

Although it’s impossible to prevent cracks caused by shrinkage, there are some ways to mitigate the process during the construction phase. These can include reducing the effects of climate by using temporary windbreaks and sunshades or adjusting the water-to-cement ratio in the concrete mix.

Settlement and Basement Floor Cracks

Settlement is another common cause of basement floor cracks. Over time, it’s natural for some shifting to occur underneath homes. In fact, homes are constructed with approximately one inch of soil movement in mind. Some homes are even designed with a four-inch allowance. In new homes, settling should only last a maximum of 24 months after being built.

Sometimes, settlement happens when the home was built on improperly compacted soil or when an inadequate base (such as sand) was used. A self-levelling cement product from a local hardware store can help mitigate safety hazards from the uneven surface produced.

Basement cracks caused by settlement issues are problematic when there are also gaps between the floors and walls and/or walls and ceiling, the walls pull away from each other or there are cracks on the walls (particularly near corners). Doors and windows that fail to open seamlessly and floors that start sloping can also indicate a serious settlement issue. If left unrepaired, the cracks will only worsen and considerable foundation damage can occur.

Cracks Caused by Heaving: A Cause for Concern

Basement floor cracks that also heave the slab upward are serious. Indicative of soil expansion underneath the concrete, cracks caused by heaving should never be ignored.

Repairing heaving-caused damage requires a foundation expert. Repairs could involve replacing the basement floor and/or installing an interior drain.

To mitigate the risk of future heaving issues, water should be redirected from your home’s foundation by properly grading the foundation, installing proper guttering and downspouts and installing drain tile around the home’s exterior that connects to a sump bucket.

Conclusion

Most of the time, cracks in the basement floor are nothing to worry about it. But if significant cracks are noticed in your basement, contact a trusted foundation contractor to complete an inspection and to identify their damage potential.