There are few instances more frustrating than when the renovation of a structure with concrete floors is underway, and then you find out that the flooring surface is either pitted or out of level.
In most circumstances, a general contractor will simply trowel conventional concrete or grout from a bag mix onto a rough surface to smooth it out or add too much water and pour the concrete to level it. This may look fine at first, however, concrete doesn’t bond well to existing concrete without a massive amount of effort put into surface preparation and failure of the new surface is guaranteed over time.
A little-known secret is that epoxy is actually a much better bond maker with concrete than with concrete itself. Epoxy can be used to prime a concrete slab to prepare it for a concrete patch or self-levelling concrete.
First, the surface is prepared via grinding or shot blasting, depending on the level of damage that currently exists within the floor. Then, 100% solids epoxy is squeegeed onto the floor and sand is thrown into the wet coating until rejection. (Definition: “Until rejection” means the surface is completely over saturated with sand and you can no longer see the epoxy.) This creates a nice rough surface for the new layer of concrete to adhere to. It also provides a built-in vapor barrier.
If the surface being repaired is to be a wear layer or a surface that will receive no further flooring of any kind, then an epoxy based, rather than concrete based, self-leveller can be specified. Epoxy based self-levellers are similar to the epoxy primer described above, in the way they bond, however instead of broadcasting sand into a primer, the applicator will mix smaller sized sand with epoxy and pour it onto the floor. This will result in a level, smooth, visually appealing and contamination resistant surface. Not only that, this type of self-leveller is more impact resistant than concrete versions.
Self-levelling concrete is better suited to areas that need to be levelled or smoothed to prepare it for further flooring such as hardwood, linoleum, tile or other traditional flooring types.
The key thing to remember here is that when levelling out old concrete floors, the most important thing is to prepare the surface and remove contamination. Without this necessary step, your efforts will most likely be in vain.
Contact a qualified flooring contractor today to have your concrete slab evaluated and a system specified.