Since you’re here, there is a high chance your concrete floor is not level and you’re wondering how to level uneven concrete floor. There might even be a situation it sags or tilt toward one side of the room.
Depending on how it happened, the situation might feel overwhelming. The more money involved, the worse it probably feels.
No worries, this article will run you through how to level a concrete floor with the self-leveling compound. Leveling concrete floor ain’t rocket science and I’m pretty sure DIY spirited person, who doesn’t fear mixing and spreading the compound, can handle it with proper planning.
Before you can begin leveling your concrete surface, you need to remove the clutter and wash the concrete floor. If it isn’t nailed down, remove it, otherwise, you may end up with a big mess. It’s always best to have enough room when working on the floors. Everything on it is most likely on the way.
Once you have everything out of the room or off area, it is time to clean the surface thoroughly. Take a stiff-bristled boom and sweep the concrete floor. Sweep in the corners to remove dirt and other debris.
The surface must be clean before applying the primer and self-leveling compound, or it will not adhere properly. What doesn’t adhere properly will come off with time and for me, that means wasted money and time even more if you process the floor further with floor coatings, etc.
Now there are at least 2 ways to go about this depending on where your floor is; washing and grinding. Both will work out fine, I might prefer grinding depending on how uneven the floor is.
Tips before starting
As always, there are some tips for easy success that people new to working with cement products might not think of.
- The self-leveling compound bag must be dry. If it’s not dry, there is a high chance of cured bits mixing in that will mess up your pour. Usually, these moist bags are at the bottom of the pallet, near the ground at the store.
- Get a big bucket that comfortably fits the mix of dry bags and water needed. It has to have a level bottom so it will mix well and it must be able to handle the mixing. These usually don’t cost much as they are consumables in construction.
- Use hand warm clean tap water for mixing. Unclean water will make a nonoptional compound mix.
- You only mix the product once. Cement to water ratio is a must to follow for strong cement bonding. If you mix more water in after using the compound, it will have more water than the part you used before so it will be weaker.
- Have all your tools ready before you start mixing. You have a time limit that you don’t want to use searching tools.
- Your time limit is unforgiving, after a certain time the product is unusable. For that reason plan the pour well so the compound will level.
- For wide areas trowel might not be as good a tool as a wide plastic squeegee for spreading the compound. Personally, I use that for all sizes of rooms as it enables me to stand straight.
Plan A: Wash The Concrete Floor
Once the surface has been swept and there are not a lot of uneven surfaces, it is time to clean the surface of your concrete foundation. One way to clean it is to use a TSP mixture or trisodium phosphate.
Combine 1/ 2 cup of TSP with 2 gallons of hot water. This mixture will remove all the grease and dirt the broom missed or could not remove.
Scrub the concrete floor with a mop. It is important to wear gloves when using TSP. This is a powerful cleaner and it will burn the skin if it comes in contact.
It is also a good idea to wear safety glasses to protect your eyes. If the concrete is in a room in your home, make sure you have adequate ventilation. Turn on a fan and open the windows and doors to carry the fumes away.
Once the entire concrete floor is cleaned, it is time to rinse it. Fill another bucket with clean warm water and then use a mop to rinse the TSP off the foundation. When the water becomes dirty, change it. You don’t want to rinse the floor with dirty water or you won’t accomplish anything other than spreading the dirt around.
Let the concrete dry now.
Plan B: Grinding concrete floor with a hand grinder
Another way to prepare the floor is by grinding it with the machine. If this route is chosen, it’s best that you have a good construction vacuum available and a floor grinder that can bite into the concrete.
There are many kinds of floor grinders so it’s good to check the size of the floor and make a decision based on that. The bigger grinders need a little practice, so I don’t recommend that if you haven’t touched one before.
When should we choose this route? I’d do mechanical grinding when there are a lot of uneven surfaces. There are bumps on the floor and other things like that.
The self-leveling compound is fast to use, but it’s no miracle maker and can’t cover spots that are way higher than the rest of the floor.
After you finish the grinding the floor needs to be cleaned carefully with the vacuum. All the dust in there will only weaken the adhering of the concrete self-leveling compound.
Repair concrete cracks
Before you can level the concrete, you need to fix any holes or cracks that are in the existing surface. There are more than one ways to do this, but I’ve chosen two options again.
The first option is to use a latex concrete caulk that fits into a calk gun. Fill the holes or cracks with the caulk and then take a trowel to remove any excess. Apply and leave it to dry according to the manufacturer’s directions.
The second option is to use a mortar mix to fix the cracks and holes. We mix a little bit in a bucket and go through all the cracks and holes with a trowel. Remember to leave the concrete surface level so no bumps will distract us when we do the leveling.
When the latex concrete caulk or mortar mix on the concrete has dried, it is time to apply the concrete primer. Stir the primer well before using it to ensure it stays on the cement.
The primer is applied with a paintbrush or roller. If you have a large area, a roller will do the job in a shorter amount of time and it will be easier on your back. Read the manufacturer’s directions to know how long the primer needs to dry before proceeding.
Not all products need the primer, you should check what your self-leveling compound manufacturer says about their product.
Find the low areas
Discover the areas where the floor is unlevel. This is done by placing a leveling bar on the floor and moving it across the cement. Make a mark on the low or uneven sections, so you know where to pour the self-leveling adhesive. Red is a pretty good color that can be noticed on the concrete when marking.
Apply self-leveling adhesive compound
Attach a mixer hook up to your drill. Read the directions for the proportions of the self-leveling adhesive compound and water to use.
Pour a little bit of water into the adhesive and mix with the drill attachment. Do not pour all the water in at once. The amount of water needed is different with every bag. It also depends on the amount of humidity in the air.
You need to mix it for a few minutes and let it sit for a few more minutes. It will feel thicker after a while, but when you mix it once more quickly it should have all the needed properties now. Check the bag instructions as I’m giving notes on general memory.
NOTE: Check your product so you’re not using fast curing self-leveling compound. These are not for beginners to use as they must be mixed and spread fast.
When the self-leveling adhesive compound is the right consistency, pour the floor-leveling compound over the concrete. Try to pour the mixture evenly and in straight lines across your concrete floor. Don’t dally in this step because you don’t want the compound to be set up before you finish.
You usually don’t have to spread it out too much because gravity will cause the compound to flow and fill in uneven areas. You can maneuver it and smooth it by using a concrete trowel or rake.
If you’re doing the whole floor it’s good to level those extreme unlevel spots first. Then you let it cure and depending on the curing time, do the floor the next day. It all depends on the properties of the self-leveling compound, and how thick it can level.
If you feel like the size of the area is something you can handle and the product label says it can level that much, you can also do it in one go. It can be a little more challenging though.
All that’s left now is to wait for the floor to harden and cure. This takes several days and it is very important that no one or nothing walks on the surface until it is completely dry. Consult the label directions for the length of time you have to wait. After the time is up, the floor is ready to be used.
Uneven floors aren’t only the problem with the old floors. Sadly some new floors are poured unprofessionally or there might be some accidents during the pour.
The good thing is that we can also use self-leveling compounds over new concrete. It’s really a saving product if you have to install floorings that need to be installed on level ground like vinyl.
It’s good to remember that it’s also a cement product. That means most of these cure into a really hard surface that can’t be sanded conveniently.
Mechanical tools will be needed for that so I recommend taking some time and planning the project out properly. If you’re doing the project yourself, it will save some time during the working phase.