How to Level a Concrete Floor: Easy Fix

Over time your garage’s concrete floor can shift, making it an unlevel surface that is unpleasant to work on. You don’t need to hire a professional, with self-leveling concrete you can do it yourself.

Below you’ll find out how much it costs, what to do and what to watch out for.

Let’s get started.

How Much Does It Cost To Level A Garage Floor?

If the floor only needs a couple of touch ups, then you can use self-leveling concrete. The price will vary significantly between $1.50 to $5 per square foot, but the average would be on the lower end about $2. This would work out to about $800 for a 20’x20′ garage.

If the floor has sunk a fair bit and you want to use a “jacking method”, the cost will be significantly higher. It can cost anywhere from $500 to $2000, with a very rough average being $1000.

If you decide to remove the entire slab, the cost can be significantly higher than the cost of pouring self-leveling concrete or jacking the slab. This is because you have to pay the cost of removal and disposal, along with the cost of installing a new concrete slab.

A very rough range would be between $6 and $15 dollars per square foot which could end up between $2000 and $6000.

Using Leveling Compound

If you only need a thin layer to level out your floor, then you can choose to use a leveling compound. The steps you need to take are as follows:

1) Clean the Floor

This is probably the most important part of the whole project and includes removing any old debris and dust, as well as any grease or other contaminants. After you remove the grime, it’s a good idea to pressure wash the slab with water.

2) Apply A Primer

A primer is important because it ensures a good bond between the existing concrete slab and the self-leveling concrete.

3) Mix The Self Leveling Concrete and Pour

Ensure that the self-leveling concrete is thoroughly mixed. Once it is mixed, pour the concrete.

4) Squeegee or Trowel The Floor

After pouring the concrete use a squeegee to ensure you cover the whole area. Even though the concrete is “self-leveling”, it is still a good idea to push it around to ensure a perfectly level surface. Another good reason to push around the concrete is to get a more uniform looking finish.

5) Let The Concrete Dry

Depending on what the manufacturer recommends, you may need to add some curing compounds or take other steps to ensure it cures properly.

Once you have completed these steps, you will find yourself with a nice, level, concrete floor.

Using Slab Jacking

Slab jacking is when a material is placed under the existing concrete slab in order to raise the height of the slab. The most common way to slab jack is to drill holes in the existing concrete slab and insert a special foam in these holes. The foam will go under the existing concrete slab and push up the slab to the required height.

In order to slab jack, you need to do the following:

1) Drill holes 

These holes must be strategically placed in order for the slab to rise evenly.

2) Insert the foam

Using a special spray gun, blow the foam through the holes so it goes beneath the slab. The foam will lift up the slab. You will need to insert the foam in the various holes in order to get the slab to rise everywhere.

3) Take measurements to ensure you achieve the correct height

Use a level or a pre-drawn chalk line to determine if you reach the correct height. You may need to add more foam just to top raise the slab to the exact height. Depending on the job, you may draw lines indicating the final height prior to inserting the foam.

How To Level A Garage Floor That Slopes

In some situations, you need to ensure your floor has a little slope. One of the reasons for this could be proper drainage. When working with this kind of situation, you cannot use a self-leveling concrete.

In order to level (flatten) a floor which requires a slope, you must do the following:

1) Set up your perimeter

This involved using pieces of wood and creating a “mould”. You need to ensure the height of the form matches the exact height of your final product.  

2) Pour the Concrete

Pour the concrete between the formwork which makes up your mould. You cannot use a self-leveling concrete since you wish to have a slope once you finish.

3) Remove top layer of concrete

Using a straight edge or a “screed” you need to remove any concrete which is higher than the formwork. By running the straight edge along the wood forms, you will achieve a surface which slopes exactly as you planned. 

Should I level my own garage floor?

Deciding whether you want to level your own garage floor or use a professional is a difficult decision. The major risk is making a mistake and having to tear-out the entire slab.

If you have some patches and can use a self-leveling concrete to level it out, you can probably do it yourself. It is important to perform all the steps including cleaning the existing surface if you want your new slab to last.

If you have major issues and need to do more than top-up a couple sections, it could be worthwhile to hire a professional. Although many people are able to do the project themselves, there are many risks if you are inexperienced, and the costs to repair any mistakes could be significantly higher than the cost of hiring a professional.

The other problem for those who do it themselves is they need special equipment to perform the task. In some situations, you can rent the equipment, but in other situations, it doesn’t make sense to buy equipment if you are only going to use it once.

Learn more: Can you pour concrete over existing concrete?

About Roy Cohen

I'm Roy, founder of Hack My Garage. I started out like most not knowing how to hammer a nail, but now I know more than most people about home improvement and DIY. I want to spread my wealth of knowledge with the world and hope to make it a better place.