How to Flatten an Uneven Concrete Garage Floor

When balls start rolling toward certain walls, you may notice that your garage floor is no longer flat. This may happen due to various reasons.

There are several options for fixing uneven concrete garage floors. Nonetheless, I have gone through the trial and error process and discovered the most efficient method that will do the job.

However, you may require assistance if you are unfamiliar with the skills utilized.

How to Flatten Uneven Concrete Garage Floor

Why a Garage Floor May Become Uneven

There might be several causes for an uneven floor, but we’ve compiled a list of the top five:

1. Moisture

If you live in an area where it rains frequently and floods, this might be one of the causes of your garage floor being cracked and uneven.

Water causes the concrete to weaken over time. Any continuous fall of fluids can also transform your garage floor into an uneven place.

2. Compaction

This one is not on you but on the builders who did the compaction of the soil! Soil needs to be firmly compacted so that it doesn’t shift under the floor.

3. Climate

Concrete prefers even temperatures. For example, the concrete will expand with heat and contract with cold. If your temperatures vary between extreme hot and cold, the concrete may be stressed, leading to cracked flooring.

4. Soil Condition

Uneven flooring is frequently caused by soil conditions. When the soil on which the concrete is placed becomes too dry, the soil expands in volume, and the concrete cannot cope.

5. Poor Foundation

Poor foundation is another major cause. If the concrete mix is not carefully prepared for your garage floor, it will most likely fail. Concrete is extremely sensitive.

Does my Garage Floor Need to be Leveled?

The answer is dependent on the depth of the cracks or the unevenness of your garage’s floor. Nevertheless, leveling a garage floor is a choice when the damage is not too much and can be solved easily.

For more extensive damage, it may be better to call in professionals to fix the damage.

But if your damage is limited, you can try my method. This method is less expensive and requires very little assistance. However, to do it correctly, you’d need a considerable amount of time and certain expertise.

How to Fix Uneven Concrete Garage Floor

Undoubtedly the only way you can fix and level an uneven and cracked garage is by using the famous Slab Jacking method. Here, we lift the concrete slab back to the position it was originally in.

These tools will provide useful for leveling your garage floor:

  • Level
  • Drill
  • Concrete

Here’s how you do it:

Step 1: Determining the Uneven Spots

Determining the Uneven

You’ll need to figure out which area of the floor is uneven and needs slab jacking to balance it out. To determine the uneven space in your garage, use levels or even string lines.

Step 2: Setting Up the Drill

Setting Up the Drill Machine

The first thing you need to keep in mind is the diameter of the drilling. You need to drill through the concrete here so having the correct number is very important as you will inject the foundation from here.

We recommend you use a drill with a diameter of about 3.5 inches to perfectly inject the cocktail.

Step 3: Drilling Hole in the Floor

Drilling Hole in the Floor

In this instance, you must drill holes in the uneven sections. The amount of holes you need depends on how uneven your concrete garage is.

However, we are unable to give you a precise estimate of how many holes you will need to drill. It is entirely dependent on the area you are trying to cover.

If you have the necessary experience, you will be able to tell. But, if you don’t, you’ll have to recruit someone who does.

Step 4: Prepare the Concrete Mix

Prepare the Concrete Mix

You’ll need to make your concrete mix for this step. To build your mix, combine sand, gravel, and ash with water. Many stores sell concrete in pre-mixed bags, which you will need to combine with water.

Step 5: Injecting the Mixture

Injecting the Mixture

There has to be a place where you can inject the mix into the the holes. You can do this with slab lifting pumps.

Making multiple holes rather than just one serves two purposes. The first is for lifting the slab, and the second is for filling voids.

Spreading and providing the highest lift capacity by putting the concrete mix through one hole will raise the uneven floor. On the other hand, injecting into the other holes will push the entire slab and fill up the gaps.

Step 6: Cover up to Finish

Cover up to Finish

After you’ve finished lifting, you’ll need to fill up the holes, otherwise, what’s the point? To fill the holes, simply use cement and a scraper to fully cover them up and level them with the floor.

That’s it! The uneven concrete garage floor has been effectively fixed.

However, you won’t be able to utilize the garage right away because it needs to recuperate before applying any pressure. Nevertheless, you can walk on it. In most cases, your car should be ready to be parked there within 3-4 hours.

How Do You Level an Existing Garage Floor

Sometimes your garage floor may tilt or lean without cracking or becoming uneven. It’s no longer but it’s not damaged.

While most individuals are stumped as to how to level a concrete floor, we have come up with a cheap and effective way to level a concrete floor. As a result, you can do it affordably yourself.

Let’s see how to do it in a step-by-step manner.

Step 1: Baseboards

The first step would be to remove all of the baseboards along the walls’ sides. You probably don’t want them to get messed up.

Step 2: Prepare the Surface

Clean the surface of your floor correctly with anything that can draw out pressurized water. Especially where the surface is too uneven.

Step 3: Prime the Floor

You’ll need to prime the floor with a mixture of your floor primer and water. In most cases, the ratio is 1:3. You can also buy garage floor-specific primer, like Rust-Oleum Concrete & Garage Floor Recoat Primer*.

Step 4: Prepare the Solution

Take a bucket and mix concrete with a self-leveling compound, such as this Custom BLDG Product*. Stir it for a few minutes. It should be fairly liquid – not as thick as mud.

Step 5: Pour the Solution

Pouring the solution correctly is the toughest job. Slowly pour the solution into the uneven parts of the floors. You will notice the solution spreading out to provide a level surface

Step 6: Scrape the Mixture

After giving it a minute, take a long handle scraper and gently mix the solution.

Step 7: Wait Till it Done

Your part of the job is done! All you have to do is wait a few hours and your garage floor should be more level than it was before.

Garage Floor Leveling Compound vs. Slab Jacking

Now that we have gone through both methods, you may have trouble choosing the appropriate one.

Well, we can always do a Pros and Cons list for you to find the perfect fix. Let’s check it out!


Talking after a lot of trial and error, slab jacking is the most effective one here. If you think about it, the leveling compound is only used to give a finishing touch to the floors. Whereas, slab jacking will provide you with an almost new-built foundation under the concrete.

Undoubtedly, the slab jacking method will last way longer than any leveling compound!


Slab jacking can get expensive and complicated compared to buying leveling compounds. You need for extra tools for slabbing. Whereas, slabbing takes only a few household tools.

Additionally, slab lifting may involve the hiring of certain experts in this field. If you have enough time on your hands, you can level your floor without any prior experience.

Dry Time

If your garage is constantly in use, leveling is not a good idea. You won’t have enough time to wait for the concrete to dry and be ready to use with leveling chemicals.

On the other hand, slab lifting requires more effort than leveling but saves time. In a few hours, your unevenness will be gone, and you’ll be able to resume your usual schedule.

Can You Use Self-leveling Compound On Garage Floor?

Using a self-leveling compound for leveling low spots on the concrete garage floor is doable. Furthermore, when you don’t have any assistance, self-leveling chemicals are a major bonus.

Remember to prepare your garage floor before you begin pouring compounds into it. It will not fix your uneven flooring but instead worsen them. Moreover, spreading the compounds properly is another thing to keep in mind.

What Do Uneven Floors Mean?

After a given amount of time, the foundation of the floor can no longer keep up, resulting in an uneven floor. An uneven floor might indicate something that isn’t quite right. Uneven surfaces include anything from slanted floors to cracks.

There are a lot of problems with an uneven floor. To begin with, people are just uncomfortable walking on an uneven surface. Second, because of its defects, it detracts from the environment of the garage or area.

Additionally, if uneven flooring goes overlooked when moving heavy items in a garage, it might cause injury. The most common issue with an uneven floor is that the garage door does not open correctly because of the slant.

How Much Does Self-Leveling Cost?

The question is can you do the self-leveling by yourself?  If you hire workers, the overall cost of the project will be higher. Likewise, if you do it yourself, the cost is significantly reduced by a few times.

However, the cost of the self-leveling concrete is $1.80 to $5 per sq. You can factor in the cost of labor in your area.

Can you Level Garage Floor With Thinset?

If you want to place tiles on your garage floor, you may use thin-set. Nevertheless, thinset can only be used with cement floors, so keep that in mind. If you have concrete flooring, thinset is not a good choice.

However, if you only have a few minor holes in your flooring, a modest amount of thinset would suffice.

Can you Use Cement to Level the Floor?

It’s impractical to level floors using cement. Cement cannot be expected to perform like concrete.

Furthermore, cement is an unstable material to utilize for floor leveling. You may like the effects at first, but in a few days, you may regret it.

How to Resurface a Concrete Garage Floor

Small cracks of half an inch can be resurfaced so they no longer absorb liquidse. Resurfacing will fill up cracks and make the surface as smooth as sparkling.

Let’s see how to do it correctly!

Step 1: Cleaning

Oil and sticky materials are typical in garages. Clean the floor well with a detergent first. After that, take a blower and use it to soak up all of the leftover floor residues for a thorough clean, which is critical.

Step 2: Removing Adhesives

Scrape off any paint or adhesives from the floor that might harm the resurfacing process with a scraper.

Step 3: Moisture

To add the last touch of cleaning, you should moisten the floor with water and utilize pressured water.

Step 4: Mixing Floor Coat

Fill a bucket halfway with water and mix the floor coat thoroughly. After a minute, give it another stir to ensure that the solution is smooth.

Step 5: Fill the Holes

Take the solution and put a limited amount of the floor coating in the holes and don’t overflow.

Step 6: Effective Scraping

Take the scraper once again and carefully slide it to one side and then to the other. Always remember to be kind. After scraping a few times on a single line, steadily spread the coating out and scrape.

How Much Does it Cost to Professionally Level a Garage?

There are many costs involved with fixing uneven concrete garage floors.

To give you an idea, the whole cost, including the equipment, is estimated to be roughly $750. However, it is entirely dependent on the size of the area to be covered.

Final Thoughts

To summarize, there are two common methods for repairing uneven floors, with slab jacking being the most effective. The technique here is to mend the uneven floor from the bottom up, rather than the top, which may become uneven again.

Fixing it from the base will allow you another few years before it needs to be fixed again. Thus, making it the most durable option.

However, I must also mention that this is a pricey repair. To accomplish so, you’ll likely need to hire pros unless you work with concrete regularly.

In contrast, with self-leveling, you would only need a leveling compound and little experience to do the job.

Yet we hope this step-by-step guide regarding how to flatten uneven concrete garage floor has helped you evaluate every possible option.

*Paid Link: As an Amazon Associate, I earn from qualifying purchases. Should you decide to purchase a tool through this link, I will get a small commission. The price of the tool won’t be any different to you.

Arthur Kyser Morn

Hey Guys! It's me Arthur Kyser Morn, aka AKM, the proud founder and author of Tools Auditor. I'm a content marketer, a dad of 2 lovely sons, and a handyman. I love trying out new tools, and together with my team, I've been creating helpful guides since 2017 with tools and DIY tips.

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