When installing flooring systems, both diamond grinding and shot blasting are methods used to prepare floors for epoxies and resurfacers. Let’s delve into these approaches and determine which is best for your floor installation.
Shot blasting works by using an airless, centrifugal wheel that propels blast media at a high velocity in a controlled pattern and direction. A blast wheel is accelerated at the concrete surface and contaminants that are removed land in a recovery chamber.
Shot blasting is an affordable option, but it’s not the best choice for every circumstance. When shot blasting, the machine is required to overlap areas which results in blast lines. Even if a contractor is extremely careful, shot blasting can result in pits, valleys and fractures in the floor.
When the intent is to apply thin film coatings like epoxy or urethane over the concrete, shot blasting is not the ideal method. The imperfections and rough profile caused by the shot blaster will show through these coatings.
When diamond grinding, grit sanding pads of various sizes are attached to a grinding machine. Several counter-rotating blades pass over the concrete at a pace slower than shot blasting. A vacuum system is connected to the grinder to keep the work environment dust free. Diamond grinding can be used on interior and exterior floors.
Diamond grinding results in a smooth finish, and even though it is more costly and time consuming than shot blasting, it is recommended by experienced concrete floor professionals.
In conclusion, the thickness of your coating should be taken into consideration before you select a preparation method. For applications like urethane and epoxy, we recommend diamond grinding for optimal results. For floors that are installed at 1/16” or greater shot blasting is recommended. There are exceptions to these recommendations and each floor project should be surveyed by an experienced contractor to make the proper recommendation.