What Causes Cracks in Basement Floor Concrete? Are They a Serious Risk?

By:    |   Published October 19, 2017
Visible cracks in basement floor concrete.

While every home is unique, they often experience problems that are actually very common. One of the common problems is cracks. These cracks can appear anywhere, from little cracks in walls or tiling to major cracks in basement floors. As a homeowner, you need to know what the cause is and, more importantly, how critical of a problem is it? If you’ve discovered a crack in your basement floor, learn the possible causes and how to handle them below.


Causes of Basement Concrete Cracks


The two primary parts of concrete are cement and water. After it’s poured, it cures to become solid. As the concrete dries, it will shrink. The degree of shrinkage is largely affected by temperature. If temperatures drop while your basement cures, that can cause cracks. Likewise, sweltering heat will rapidly dry your concrete – and curing too quickly also causes cracks. Even in perfect conditions, over time, your basement concrete will experience some degree of shrinkage.

While there are some ways to help mitigate shrinkage, such as controlled cracks in specific areas, it’s impossible to prevent them. There are certain areas that are more likely to develop these cracks than others, such as around doors or other sharp corners.

On the bright side, cracks in your basement floor due to shrinkage rarely result in any structural problems. However, they still open the doors for other problems like water or pests. That means they should be repaired and sealed whenever you identify them. While you should consider every crack a potential risk, most cracks under one-eighth of an inch wide aren’t a cause to be concerned.


Another common cause of cracks in basement floors is when the concrete slab begins to settle. Typically, settlement occurs when the soil beneath your foundation is too unstable to support the weight of your home and it shifts. Most homes are designed to allow for about an inch of soil movement – though some areas require the design to allow for up to four inches. In addition to soil movement, leaks in your basement and even tree roots can instigate settlement cracks.

Cracks are one of the most common signs of settlement. However, there are a handful of other signs that might indicate an issue with settling:

  • Gaps forming between the floor and walls
  • Gaps forming between the walls and ceiling
  • Walls pulling away from each other
  • Cracks on the walls, especially near corners

If you notice one of these clear signs, make sure to take it seriously. You should also look for other signs that can indicate the cracks are related to settlement. Doors or windows that cease to open correctly or floors and surfaces that noticeably slope suggest your issue could be a serious one. Settlement is a problem that only gets worse with time. Cracks will continue to form and your foundation could suffer considerable damage.

Frost Heave

During the colder seasons of the year, another source of cracks in your basement floor is frost heave. When soil freezes and thaws, it causes an expansion then a shift underneath your foundation. Like settling, this movement causes your concrete to also shift and that leads to cracks. The most obvious sign of frost heave is cracks near support columns in the flooring. With cold weather season around the corner, you should look into ways to help prevent frost heave.

Risks of Cracks in Your Basement Floor

Water Seepage

Any cracks in your basement floor open you to the possibility of water seepage. The ground underneath your foundation is full of moisture. When there are cracks in your home’s foundation, it lets pressure force the water up into your basement. Once a source of moisture exists, mold follow.

Structural Problems

Concrete basements will always crack. Fortunately, these small cracks, like those from shrinkage, rarely impact the structural integrity of your home. However, bigger cracks or those caused by instability of the soil beneath your house can lead to serious issues. If you notice significant cracks in your basement, make sure to have them inspected by a professional to identify their damage potential.

Invasive Pests

There are plenty of pests that consider a crack in the foundation to be an open-invitation to your home. While it’s likely that you would fix a crack in a wall anywhere else in your home, it’s not uncommon for cracks in basement floors or walls to go unnoticed. Even if you notice them, you may not consider them as big of an issue, especially if you don’t frequently use your basement. In addition to the other potential damage caused by cracks, this is a good reason to get them fixed as soon as possible – otherwise you might be sharing your home with all sorts of critters.

Is Fixing Cracks in the Basement Floor a DIY Job?

When it comes to foundation cracks, there is no one answer. Hairline cracks and those that clearly don’t impact the integrity of your home can be simply sealed, or patched and sealed. However, if you’re not sure, it’s always better to err on the side of caution and have an expert inspect them. In addition to the potential health risks of mold, mildew and pests, cracks can be a sign of bigger problems. If your home is at risk of major damage, it’s best to find out as soon as possible.


Protect Your Home – Schedule Your FREE 20-Point Inspection

If you’re worried about cracks in your basement floor, EverDry Toledo can help with a FREE 20-point basement inspection! We’ll help you find out if your home is at risk for water damage and which solutions will best serve you.

Contact us online to schedule an appointment or give us a call at (419) 469-5833 and schedule your inspection today!

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