How to Level a Concrete Floor That Slopes

How to Level a Concrete Floor That Slopes

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Whether you or somebody else poured the concrete, if you have a concrete floor that slopes, then you are going to have some problems. Obviously, you don’t want to build anything on a sloped floor, because that won’t do you any favors in terms of structural integrity and stability.

With that being said, having this problem is quite common. Luckily it’s not a super difficult problem to fix. Yes, it does take quite a few tools and a good deal of effort to deal with, but with that being said, with the right knowledge, you can level that floor all on your own.

How to level a concrete floor that slopes is exactly what you will learn right now.

How to Level a Sloping Concrete Floor

Let’s jump right in.

Step 1: Gather Your Materials

The first thing that you need to do here is to gather all of the materials that you will need to complete this job. First of all, you will need a hard bristled floor scrubbing brush as well as a special concrete cleaner. You may also need a metal scraper.

You will then need a vacuum or a shop vac for sucking up remnants. Other items you will also need include a bubble level (or even a line laser level), some marbles, a walk-behind concrete grinder (or a handheld grinder if dealing with small spaces), a concrete bonding agent, a concrete self-leveling agent, and a squeegee.

Walk-Behind Electric Concrete Floor Grinder

Step 2: Plan

Something to keep in mind here is that while you could always level things off yourself by grinding away a massive amount of material, this is going to be difficult and costly.

Therefore, you do really want to assess the situation first, especially the condition of the current concrete floor as well as the degree of the slope. In most cases, grinding down the high points and then using a concrete self-leveling agent will be enough to remedy the situation.

You just want to assess the situation to figure out exactly how much materials you will need to complete this job.

Step 3: Prepare the Concrete Floor

Once you have made your initial assessments, you can then move onto preparing the concrete floor to get it ready for the next steps. First of all, you do of course want to clear the area of all appliances and objects. There should be nothing left on the concrete floor, and this also includes stains, dirt, and other debris.

In other words, you want to get yourself a good floor scrubbing brush as well as a special concrete floor cleaner. When using a concrete floor cleaner, be sure to read the directions properly because these products can be dangerous. Pour the cleaner onto the concrete and let it soak for up to an hour and then use that scrubbing brush to scrub away any stuck-on debris.

You can now use a rag cloth or any other such object to remove any and all loosened dirt, as well as liquid. Once the surface is dry, you do then want to vacuum it, with a shop-vac being your best bet. Remember, in order for this process to be successful, that concrete floor does need to be 100% clean and dry before you move on to the next steps.

Step 4: Mark the Uneven Spots

In order to level your concrete floor, you first need to figure out where the uneven spots are. One of the simplest and cheapest ways to do this is by using some marbles or any other such round objects that can roll. Go to the various areas on the sloped floor and place the marbles there.

If the marbles roll downwards, you know that there is a high point, and if the marbles stop rolling, you know that there is a low point. If you do not have any marbles, you could always just use something like a bubble level to figure out what the slope looks like, as well as where the high points and low points are.

What you want to do here is to mark the high points. You don’t have to mark the low points because those will take care of themselves when you grind away the high points in the next step.

Step 5: Grind the High Spots

Now it is time to put that walk behind concrete floor grinder that you rented or purchased to use. Of course, you do want to wear protective equipment such as steel toe boots, goggles, and hearing protection when using any such device.

What you want to do now is to turn on the walk behind concrete grinder and proceed to grind away the high spots on the sloped concrete floor. Now, be aware that you do want to move quickly when doing this because it is fairly easy to grind away too much. If you grind away too much at a high spot, you are going to end up with a low spot in place of that high spot as well as other high spots surrounding it.

Therefore, only remove a little bit of material at a time and keep using either your marbles or the bubble level to check the slope of the floor. Once all of the high spots have been removed, you can then move onto the following step.

Step 6: Prepare and Apply the Concrete Bonding Agent

You will need to use a layer of concrete bonding agent in order for the self-leveling compound in the following step to stick. Therefore, what you need to do is to prepare the concrete bonding agent according to the manufacturer’s instructions.

What you want to do now is to use a paint roller to evenly apply the concrete bonding agent across the floor. You then need to wait for the concrete bonding agent to dry to the point where it is no longer wet, but is still a bit sticky. It needs to be a bit sticky for the self-leveling compound used in the following step to stick.

Step 7: Prepare and Apply the Self-Levelling Compound

What you need to do now is to prepare the self-leveling concrete agent as the instructions indicate. Once it has been prepared, use a squeegee with a long handle to spread it out all over the floor, making sure to get through all edges at the walls. Be sure to work very quickly as the self-leveling compounds like this dry very quickly.

You want to apply about 1/4-inch layer of the self-leveling compound to the floor. Indeed, the self-leveling compound will level itself, with the majority of it sinking into the low spots, thus automatically leveling the floor without you having to do any additional work. All you have to do now is to wait for it to dry completely, and then if you want you can always add additional layers.

Mistakes to Avoid, Tips & Tricks

While the above should do the job, below are some additional tips to make the process smoother:

  • If it is a large concrete floor that you are working on, you will really want to use a walk behind concrete grinder to grind down the high spots. If it is a very small floor that you are working on, such as a closet or bathroom, you may use a smaller handheld grinder outfitted with a diamond disc in order to grind down the high spots.
  • Always wear gloves and the proper protective equipment when working with concrete bonding agents and self-leveling agents as they can be quite corrosive.
  • Don’t just pour the substances onto the concrete without first cleaning and leveling it, because if you do, it’s not going to end well.


As you can see, although it does take a good deal of skill and knowledge in order to level a sloping concrete floor, it is possible to do it on your own as long as you have the right tools, know-how, and a bit of patience too.