Garage floors are an especially difficult painting problem. Extreme durability is required to withstand constant abrasion, items being dropped on it and chemical spills. The paint must be extremely hard, while still maintaining some flexibility to overcome this combination of dangers. For this reason, epoxy paint is normally used.
Epoxy paint is essentially a thinner, tinted version of epoxy adhesive. It is normally a two-part paint product, just as epoxy adhesives are. However, there are a few one-part epoxy products on the market which are specifically designed for use as garage floor coverings. I don’t understand how they can be one-part products, but still be epoxy. Nevertheless, their manufacturers label them as such and sell them as garage floor coatings.
Epoxy cures as a chemical reaction; which is different than other paint products. Almost all other paints dry by evaporation of the solvent that is in the paint. This is why VOCs are such an issue with oil-based paints. The solvents used in these products are VOCs. They must leave the paint by evaporation for the paint to dry. Due to increased regulatory requirements, more and more of these paint products are being replaced by water-based products; as water, by definition, isn’t a VOC.
Likewise, more and more epoxy paints are becoming water-based paints. From what I’ve seen, this has not reduced the quality or durability of these paints, as the epoxy still cures by a chemical reaction. Unlike other paint products, water-based and oil-based epoxy paints are extremely similar.
What makes an epoxy paint good is the percentage of solids that it contains. The more solids, the heavier and more durable a coat of finish it puts on the floor. High solids epoxies also soak in less, providing better coverage.
Coverage is a major issue for these products, as concrete is highly porous. A certain amount of the material soaks directly into the concrete, reducing the coverage area. This is hard to predict, as concrete used for garage floors varies considerably. The way that the concrete is finished has a part to play in coverage as well. The good news is that the more the epoxy seeps into the concrete, the better it bonds with the substrate.
Before using any garage floor coating, it is essential that the floor be totally clean. This is actually a bigger challenge than applying the floor covering, as garages typically have stains from oils and other chemicals. All of these, especially the oil, will reduce the adhesion of the epoxy to the floor. If the floor isn’t cleaned and prepared adequately, the covering will not last, but will flake and peel from the floor.
For this reason, it is best to apply an epoxy floor coating to new cement, before the garage is used. However, that is not always possible. If the coating is to be applied to an already existing garage floor, then it is important to take the time to thoroughly cleanse the floor.
Finally, remember that two-part epoxies have a limited working time before they cure. Check the working time for the epoxy product that you purchase and ensure that you can finish the application in the time available. Once it starts to thicken, effective application is almost impossible.
It is possible to mix only part of the product, rather than mixing the whole kit. However, when this is done, there is a very high risk that the second part won’t be exactly the same shade of color as the part already applied. Without exact measurement, it is impossible to maintain color consistency. When measuring to separate part of a kit out for later application or touch-up, remember that a 1:1 ratio may not be exact. Verify that both containers have the same amount of product in them, so that your measurement will be accurate. Check out our list of the best garage floor coatings in 2022.