Have you ever wondered why some products you put on concrete are called sealer and others are referred to as coatings? These products both form a film on the concrete, but they really go their separate ways from there. Understanding the differences and learning how to utilize each one for what its best for is a big part of decorative concrete.
Acrylic Sealers- This is the stuff we spray on exterior concrete every day. Whatever the finish of your concrete might be. If you are spraying a Cure & Seal, it probably involves some kind of acrylic resin. These resins start out as a solid substance that gets melted down into a liquid and blended with a carrying agent. This is what allows us to work with the resin and spread it out to the proper thickness. At this point the resin is just hanging out and waiting for the carrier to evaporate so it can get back to that solid state. Acrylic resin doesn't need any hardener or anything else to start the film formation and harden.
Because of its chemical makeup and low viscosity, acrylic resin will bond to pretty much any concrete surface without any profiling. The film they leave behind is less denes then that of a concrete coating. Almost like there are microscopic air pockets in the film that will allow moisture to pass up through. This is why these resins are considered breathable. Acrylic resins will also wear away over time and need to be reapplied. Resealing acrylic sealer doesn't require any abrasion of the existing surface due to the chemical bond it creates.
Concrete Coating- Concrete coatings are things like Polyaspartic, Epoxy, Urethane, or any other product that requires a hardener. These products don't all start their life out as a solid substance and if left on their own, they would never achieve proper film formation or hardness. This is why most concrete coatings products have two parts that need to be mixed together. Once these two parts get mixed, a chemical reaction will take place and the clock starts ticking. As the coating gets spread out and the carrying agents evaporate, the film will start to form and harden due to the reaction from the hardener.
Unlike acrylic resin, concrete coatings usually have a high solid content and leave a very denes film behind. If these coatings have any microscopic air pockets at all, they are really small and there is not many of them. This means that concrete coatings wont let much if any moisture pass through the coating and makes them unbreathable as well as intolerant of moisture. The density of these resins also creates the need for open pores and some profile on the surface of the concrete to ensure a long-term bond. Applying a concrete coating directly to unprepped concrete will result in little to no adhesion and generally leads to delamination after short period of time. The chemical resistance of these denes coatings means they will need some abrasion in order to recoat them down the road.
Final Thoughts- The extreme durability of concrete coatings make them great for creating long term interior floors. Things like Metallic Flooring, broadcast floors, and high wear industrial flooring are all perfect situations for concrete coatings. Acrylic Sealers on the other hand better for exterior concrete. Their breathability and bond make them ideal for stamped concrete or if you're just looking for a cure & seal. They won't last more than four or five years, but they can be reapplied fairly easily.
-Jeff Hershberger
Please send us an email with any questions you might have about sealers & coatings or anything else relating to decorative concrete. Jeff@deco-cretesupply.com
