Self Leveling Compounds and Ceramic Floor Tile

By Mark J. Donovan

If you are planning to install a ceramic tile floor it is imperative that the floor first be smooth and level. Ceramic floor tiles will crack and/or become loose over time if the subfloor is not perfectly smooth and void of bumps and valleys.

Self leveling compounds are ideal for smoothing out uneven wooden floors and concrete floors. Older wooden floors can have humps and dips associated with them due to sagging or twisting floor joists. Likewise, concrete floors typically have valleys and humps associated with them.

Self leveling compounds are ideal for feathering out the dips in a wood subfloor or concrete floor.

Preparing Wood Subfloors and Concrete Floors

In order to properly apply a self leveling compound to a subfloor it is extremely important that the subfloor is rigid. It is important to understand that self leveling compounds will not add stability to a subfloor. If the wood subfloor flexes when you walk on it, the self leveling compound will most probably break up. This will lead to ceramic floor tiles cracking and becoming loose over time. As a result, it is important that you have a solid subfloor surface before you apply a self leveling compound.

Subfloors also need to be free from dirt, dust and grime before applying a self leveling compound. Else, the self leveling compound will not bond well to the subfloor. Use a vacuum cleaner to first pick up all the loose particles on the subfloor. Secondly, use a mop, sponge or damp squeegee to lightly wash the subfloor.

Applying Primer to the Subfloor

In order for self leveling compounds to bond well to subfloors, it is critical that you roll or brush on a latex primer first. It is important that the primer fill every square inch of the subfloor to ensure a solid bond of the self leveling compound.

Once the latex primer has been applied allow it to thoroughly dry before applying the self leveling compound.

Identify Low Areas of Subfloor

Use a level, straight 2x4 or framing square and slide it over the subfloor looking for low spots. Use a pencil to circle these low areas. These areas will represent where you want to apply the self leveling compound.

Mixing Self Leveling Compound

First, it is extremely important to note that self leveling compounds set up extremely fast. You will have only about 10-20 minutes of total time to mix, pour and feather out the self leveling compound, once you mix the product with water. As a result, make sure you have all of the tools and materials handy for mixing, pouring and spreading the self leveling compound.
To mix the self leveling compound read all of the manufacturer directions first. Make sure you follow any safety procedures while working with the product, as it is usually unsafe to breath in the self leveling compound dust. A dust mask should be used to avoid breathing in the dust associated with the leveling compound.

It is best to mix the material using a power drill with a mixing hook as this will speed up the mixing effort. Make sure to mix the self leveling compound with water in a clean bucket. It is best to use cold or even ice water, when mixing in the self leveling compound, as this will help to extend the working time of the self leveling compound.

The mixture should have a loose soupy consistency. If it is too thick, it will harden very fast and will be unusable. Also, make sure to scrape around the edges of the bucket when mixing the self leveling compound. You should limit the mixing time to just 2 to 3 minutes to ensure you have sufficient time to pour and spread it.

Apply Self Leveling Compound

Once you have completing mixing pour some of the mixture into the low areas that you circled with your pencil. Allow the mixture to spread out a little before using a trowel or squeegee to smooth it out. Note: drywall tools work great for spreading out the self leveling compound.

Remember that you will only have about10 minutes to work with the mixture, so work quickly
Do not add additional water to the mixture to try to loosen it up. This will cause the self leveling compound to cure improperly and will lead to it breaking up. Instead work quickly with the spreading of the material.

After 30 minutes, the self leveling compound will be fairly set up. Usually within 2-4 hours it can handle foot traffic. The ceramic floor tile can typically be applied within 12-24 hours after the self leveling compound has been applied.

Clean Up

After feathering out the self leveling compound quickly wash out the bucket and tools with water. If you do not, the self leveling compound will become a permanent fixture to your bucket and tools.