Before you even consider laying down a sub-floor for your mosaic tiles, you have to address the concrete floor itself [source: Edisoncoatings]. The floor has to be smooth and clean. If it is not then you will not be able to use your mosaic tile grouting system properly. At the very least you will have a lot of trouble with leveling the floor. Even if you are using the recommended materials from the manufacturer you will still run into some difficulty.
How to Level a Concrete Floor
In order to get the best results you will need to prepare the concrete floor to the proper level. The first thing that you have to do is to make sure that the floor is extremely clean and clear. It is always recommended that you allow the concrete floor to dry thoroughly before you apply any sealant or grout. This should be done before you start anything else.
Most people get themselves into trouble when they attempt to install grout by themselves.
This is because they make the mistake of using self-levelling compounds. Self-levelling compounds are recommended only where there is an existing surface to grind. For concrete floors the problem lies in the difficulty of penetrating the surface in order to grind it down. The self-levelling compound will simply shred the surface as it makes its way down. This means that you will have a huge surface to grind, and therefore you are back at square one.
The next problem with trying to install a self-levelling floor compound is that you will find that it is impossible to get any sort of consistent grouting area.
Even when you use a very coarse grout pad the cracks will be too small to allow you to get a professional looking finish. Once you have finished the concrete flooring then all you have to do is install a pad of timber to fill in any gaps and to even out the surface. If you do this then you will find that you need to use a different type of concrete floor filler.
Another problem with some types of flooring is that there are unsightly cracks all along the surface of the floor. These cracks can easily be filled in, but then the whole area will look unsightly again. Cracks and dips are another potential problem for this type of flooring. The key to getting round dips and cracks is to make sure that the area under them is sealed before you apply the sealant.
Many homeowners prefer to use an epoxy resin based urethane to level uneven concrete floors.
The advantages of using this type of product are that there is no need to prepare the floors. You also do not have to worry about cracks and dips and unevenness. The only disadvantage of using epoxy resin based urethanes is that they are more expensive than some of the other types of products available on the market.
If you need to repair any kind of crack or small dip in a concrete floor then you need to use a caulk based penetrating concrete sealer.
If you have any old oil based penetrating sealant then it should also be removed prior to applying the new one. Apply the caulk as you normally would and then put a couple of layers of the caulk. The thickness of the layers needs to be carefully calculated so that the flooring will have adequate protection from the penetrating sealer. After the third and fourth layers of coating are added then you can apply the second layer of sealing compound. This second layer is particularly important because it helps to stop the water from seeping underneath the flooring and causing further damage.
It takes about two and a half days to prepare a concrete floor for installation but this is not enough time to allow the concrete to set properly.
Once the proper amount of time has been allowed to set then you can apply the new flooring without having to worry about water seeping underneath the surface and causing problems. You can do this in just about two and a half hours with an average home household mixer. This process will give you lasting protection from cracking, peeling, and blistering.