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Cracks in Your Garage Floor? Here’s What to Do

March 15th, 2023 | 4 min. read

By Sarah Etler

If you're struggling with garage floor cracks, find out when and how you should go about repairing them.


While it can be very intimidating to notice that your garage floor has developed cracks, it’s actually a very common problem that many homeowners deal with.

At first sight of cracking, you may be concerned about foundation movement or a serious underlying problem, but a lot of the time, the cracks that form are harmless, even if they do seem scary on the surface.

Here at A-1 Concrete Leveling, we’ve been repairing and preserving our customers’ garage floors for over 30 years, and in this time we’ve gotten familiar with garage floor cracks and how to fix them.

In this article, we’ll walk you through why garage floors crack, how to determine if they’re serious, ways you can prevent them from happening in the first place, and the repair options available to you if you find yourself with garage floor cracks or joints that need to be repaired.

Why Garage Floors Crack

Garage floors usually crack due to the following reasons: a lack of proper joints, and the sub-surface shifting which causes the floor slabs to settle or move.

Inadequate Joints

Concrete expands and contracts with fluctuations in temperature, but if there’s no room for this movement, the concrete can crack. 

The intentionally-placed gaps and lines running through your concrete are special joints that allow the concrete to move properly and minimize cracking (expansion joints), or the appearance of cracks if they form (control joints). 

If your garage floor does not have expansion and control joints, there aren’t enough of them, or they’re improperly placed, your garage floor is likely to crack over time due to natural expansion and contraction.


Over time, the slabs that make up your garage floor can begin to sink and become unlevel. During this process, the movement can cause your garage floor to develop cracks.

Settling is caused by many different factors, like soil erosion, improper compaction of the base materials when the concrete is installed, voids under the slabs, and poor water drainage. 

The issues that come with settling can be alleviated by using concrete leveling to fill voids and lift the slabs back up to a level position. Doing this as soon as possible after noticing the slabs are settling can help prevent cracks from forming.

Determining if the Garage Floor Cracks Are Serious

No one wants to find cracks in their garage floor, but if you do, it’s important to determine whether or not they will get worse so that you can repair them before they do.

If you’ve found minor hairline cracks in your garage floor, chances are they aren’t a huge problem. As long as they’re not exposed to any water, they likely won’t widen or worsen.

However, if you notice that a crack is getting wider, you should caulk it. It may be getting wider due to expansion and contraction causing the two opposing concrete pieces to rub against each other. It may also be worsening due to settling.

Monitoring the cracks regularly for any movement or additional damage will tell you if they’re serious and require attention. Seeking the help of a professional can also be helpful in determining why the cracks have formed and what you can do to prevent them from worsening.

Repairing Garage Floor Cracks and Joints

Concrete garage floors are different from the standard concrete you find in outdoor driveways, sidewalks, patios, etc. Because garage floors are not usually exposed to water, they have different repair needs than their exterior counterparts.

Garage floors also have a smooth finish, and getting the crack or joint repair to match is difficult for this reason. To repair your garage floor cracks, you will need to decide between using:

  • Epoxy
  • Polyurea
  • Polymer concrete caulk

Pro Tip: Consulting an expert is the best way to find out which repair method makes the most sense for your particular garage floor cracks or joints.


Using an epoxy crack filler on your garage floor is a sandable option that can help reinforce the crack rather than only seal it up. There are some DIY epoxy products available, but the best option when using epoxy to fix garage cracks is to get it done professionally.

Filling garage floor cracks with epoxy can be labor-intensive and requires specialized equipment to do properly. Prepping the breaks by widening and cleaning them, along with filling any weeping points before the application, is necessary for good adhesion. In addition, a good finished product relies on knowing when to properly shave down the excess epoxy.

Professionals will have access to various types of construction-quality epoxy to meet the needs of your specific repair, plus the tools and know-how to get the garage floor cracks sealed up right.


Polyurea is a two-part, fast-setting, semi-rigid repair liquid used to mend cracks in concrete and repair spalled or damaged joints. Similarly to epoxy, using polyurea on garage floor cracks helps to reinforce breaks and strengthen the concrete.

Installing this repair liquid is similar to repairing cracks with epoxy, as there are many steps involved in the process, and it requires specialized equipment to do well. 

Concrete Caulk

If you’re not worried as much about strength and would rather just make sure the cracks are sealed up, applying a regular polymer concrete caulk will do the trick. However, flexible polymer-based concrete caulking is preferred when concrete movement is expected.

It’s important to keep in mind that this alternative is not sandable and paint might not stick to its surface, so if you plan on painting or applying a surface coating over your garage floor in the future, sandable epoxy or polyurea might be a better choice.

Preventing Garage Floor Cracking in the First Place

The best way to deal with garage floor cracks is to prevent them from happening at all. 

Control and Expansion Joints

If you are planning on building a new home or adding an additional garage to your existing house, ensuring that the garage floor is installed with the proper control and expansion joints is crucial.

This will allow for proper movement between the floor slabs with the expansion joints and will coax the cracking into the hidden valleys of the control joints.

Lifting Settled Concrete

It’s also crucial to repair sinking slabs at the first sign of settling. If you wait until they have settled too far, the slabs will likely crack before you can get them lifted into the proper place.

Should You Repair Garage Floor Cracks?

After learning all about garage floor cracks, you’re ready to decide if they need to be repaired, how you can go about it, and what to do to help prevent new cracks from forming in the future.

A-1 Concrete Leveling has worked with countless homeowners across the country to repair their garages and prevent future damage. If you’d like to see what A-1’s concrete repair services can do for your garage, find your nearest location to request a free onsite estimate!

Sarah Etler

Sarah Etler joined A-1 Concrete Leveling after receiving her Bachelor of Arts degree in English from Northern Kentucky University. As A-1's Content Marketing Manager, she works closely with industry experts to produce content that will best answer questions related to concrete repair and maintenance practices. Sarah loves living a life full of discovery and is excited every day to see what new things she can learn and share with those around her.