If you want to install any kind of floor, you should have as level ground as possible. If it’s not level, the new floor might not sit well or it might crack from the joints. Then, when you try to place furniture in the room, those can’t be placed perfectly on the uneven ground.
For these reasons, it’s good to know how to use floor leveler on the concrete floor, or self-leveling compound in other words as these are most often marketed. A self-leveling compound is a high-flow compound and once it’s mixed and poured, the gravity will make it flat.
Using self leveling compound on different surfaces
All the floors in the house can be uneven. It might be like that since the pouring of concrete, or maybe the floor has been ground too heavily at some point. There are so many reasons that it’s pointless to list them.
That being said, you can use self-leveling compound over new concrete as well as old concrete. You just need to roughen the surface so it will adhere well. The same goes for old concrete as well.
With the compound, all the concrete surfaces can be made as level as possible. It’s a good combination if you want to install electric floor heating for example.
These compounds aren’t only for concrete surfaces. You can even use cement-based self-leveling compound on wood subfloor to make it more flat or even ceramic tiles. If you don’t want to remove old flooring when you build a new one, it’s one way to take a shortcut.
How to prep floor for self leveling compound
Now, how to level uneven concrete floor? It all starts with preparation, like every other good concrete project.
Step 1: The self leveling compound needs to adhere so first thing we should do is fixing the floor if it’s damaged. Here is a guide on how to fix concrete cracks.
Step 2: If there is something to be fixed, you will probably clean the floors while doing that. It’s recommended so the fixes will adhere to the floor.
If you have a wooden subfloor go through the screw holes, cracks, and joints with a caulking gun and some elastic fixing compound. It won’t crack so easily when the ground lives.
If your floors are OK, then you need to take this step and clean the floors thoroughly with vacuum. As dust free as possible.
Step 3: Now you should spread self leveling concrete primer on the floor. You can do that with thin haired paint roller or one time use paint roller.
Start by doing the borders around the room with a paintbrush. After the borders are done, use the roller to spread the primer to the whole floor surface. Start from one wall and in typewriter fashion move to another end.
With concrete floors, this might not be necessary always, but if the manufacturer label of the self-leveling compound says to use it, I would. Wooden subfloors I would always primer.
Don’t primer yourself into a corner.
How to use self leveling compound
It’s time to learn how to use self leveling floor compound. There are many ways to spread it, but I’ll explain how I do it.
You need a big bucket where you can mix 2 bags of self-leveling compound, a hand trowel, and something to spread it on the floor. I prefer a trowel with a long shaft so I can spread it while I stand. The best thing is, the self-leveling compound is so liquid it doesn’t have to be troweled to the ground.
Step 4: Mix 1-2 bags of self leveling compound on the bucket. First measure water for the amount you will be mixing and then mix half of the compound with it.
Soon place the rest of the compound into the water and mix it for the time it says on the manufacturer label. Usually, these need to stand wetting 3-5 minutes before the final mix.
Step 5: Pour the self leveling compound into ground. You will see it’s almost like thick water in there.
Step 6: Spread it evenly on the floor with the trowel. There should read how thick layer you can do with the compound on the bag.
I usually refer to that and play it by the eye when I spread it all around the floor with the trowel. Now if you need to be more exact, you should use markers around the floor that tells you the height the compound needs to be.
Step 7: Repeat steps 1-3 until the whole floor is covered with the self-leveling compound. Here it’s good to work in typewriter fashion as well, always pour more near the just poured surface so it will mix well with the older compound on the ground.
Cheaper alternative for self leveling compound
If you’re looking for a cheaper alternative to self-leveling compound it might be hard to find. Different floor compounds can be used as well, but making the floor flat with them will take some skill that many might not have.
When I work with balconies, I check the low parts of the floor with level and mark them with a circle. After that, I’ll make some floor compounds and fill the puddle spots and screed them level with the rest of the ground.
After the low parts have been filled, I’ll do the whole floor with thin layer of floor compound. Notched trowel can be good here.
You pour the floor compound and spread it with a notched trowel. After that, you turn the straight edge down and smooth the surface. Now you have even a layer of floor compound everywhere.
It won’t be as flat as self leveling compound, but it’s pretty near.
How to fix self leveling compound mistake
Sometimes you meet with a self-leveling compound failure. It’s quite possible that someone has mixed a fast curing product with slower curing one or the process has been left halfway. Or you might notice that the self-leveling compound is not flat.
Uneven floor after compound
If the floor is left in a mess, not flat and uneven, you might need to grind some of it off before doing it again. If the situation is not that bad, a grinding stone will work well enough to get the high parts flat.
If it’s done with fast curing compound, grinding it might be quite hard as it cures quite hard. If the floor is no good you might need to do it again.
Dust and flaking
If the just done self-leveling compound is turning to dust under your feet or flaking, it’s a sign of too much water in self-leveling compound when the work was done. It’s important to refer to the manufacturer labels because when it’s liquid it’s hard to tell if there is enough water or too much.
That kind of floor has to be grinded away as well and be redone.
You should know how to use floor leveler now. It’s simple, but perfect execution needs some planning. The mistakes can be easily avoided like that as well.
Make sure, if you’re a beginner, that you don’t get the fast curing floor compound. It will cure really fast and if you’re not familiar with it, it will cure on your hands and the floor won’t be good.
The slow curing ones are a lot easier to handle, even when they cure for some days. I’d rather use them myself as well if I’m not in a hurry.