Types of concrete surface preparation for epoxy floor systems

Preferred Prep Methods

The standard around here in the northeast and some other parts of the country for the best type of concrete surface preparation for epoxy flooring is shot-blasting and dust-free diamond grinding. Those are the two basic preferred methods. You can add scarifying, depending on what you’re taking off and removing. Some people do acid washing.  

Surface Prep Methods for Epoxy Floor Systems

Acid washing shouldn’t be the preparation method used for an epoxy floor covering.  You shouldn’t put water on a floor before you have to coat it since epoxies are hydrophobic anyway.

Now, which form of preparation is the best for concrete floor systems? It depends on the system. If you’re going with a thin‑film system, diamond grinding tends to be the best. Because, if you shot-blast something, you can leave a profile that even thin‑film resin floor systems can telegraph through.

So, what installers should do on thin-film jobs (and this will all depend on the equipment of the people that are doing the job), is to shot-blast the floor first, and then come back and diamond grind the tops off.

Diamonds are very expensive, and if you already have shotblasting equipment you can do the major part of the removal with the shot, which is inexpensive, and then come back with the diamonds and just clean it off nice and easily.

With any epoxy flooring over an eighth of an inch thick, or an eighth of an inch or thicker, it just makes sense to shotblast. There’s really no need to diamond grind after that; typically.

Using the scarifying method just depends on what you’re doing. There are certain types of removal.  They make different kinds of pieces of equipment to do many, many different things.

Scarifiers, scabblers, diamond-headed machines that have a certain kind of blade on them, tile removing machines with thin blades that you can ride and snap epoxy flooring systems from the floor and whatever it takes to get the job done.

As long as the installer isn’t coming in there with the sandpaper and sanding the floor, using some acid, sweeping the floor off, and laying the floor down, facility managers really don’t care what method is used, as long as it’s all dust-free and they don’t make a big mess.

Are they going to shotblast, are they going to diamond grind, are they going to scarify, etc? Does each individual system have a way of prepping that’s preferred? Sure. No doubt about it.

Epoxy Coating Application Thickness Considerations

Say you’re doing thin film on a garage floor or using an epoxy garage floor coating using epoxy floor paint. You go to a thin-film, you do shot-blasting, and actually, hairline cracks will then open up more. So you create more work for yourself.

And when you pre‑patch meandering little hairline cracks that have been opened up by a shotblaster, they become very smooth spots, and they’re very noticeable underneath the thin film.

So, if you shotblast first and then diamond grind all the tops off, you bring everything back down on the plane.

The other reality is this: you can only do what you’re getting paid to do. So, if someone turns around and says, “I don’t want to pay for that,” then they don’t get it.