You want to upgrade the look of your concrete floors, but you don’t want the major cost or inconvenience that comes with entirely replacing concrete.
Whether home or business flooring, you can update your concrete with an acid or water-based stain. A concrete stain creates a chemical reaction that will bring out the natural colors in your concrete, pulling out colors like tan, cola brown, black, red, and green. Concrete can look strikingly professional and luxurious with the right stain.
But before you apply a stain, you need to prep the floor thoroughly for staining. An effective stain starts with a clean and clear surface. If you don’t, you’ll be left with floors that are irreversibly marked and damaged.
So let’s dive into the prep process for removing any contaminants and marks on your concrete flooring.
Check for contaminants.
Start by spraying your concrete floor with a gentle spritz of water. This will help you figure out if there are contaminants on your floor. If the bare concrete floor darkens and the water penetrates, there is not a sealer present. If the floor doesn’t darken and the water beads up, the area is sealed and the sealer must be removed mechanically..
Glues, paints, caulking, and mastic can all cling on to concrete, so this can be a challenge to remove when it comes time for concrete staining. It’s important to rid the floor of all contaminants first, because the chemicals of an acid stain can have a chemical reaction with these materials (rather than the concrete itself). This can permanently damage the floor.
Scrape the contaminants.
Using a floor scraper, pull up as much of the mastics and glues from the floor as you can. If the glue isn’t coming up easily, don’t force it as this could damage the floor.
After you’ve scraped up all the excess contaminants, it’s time to dissolve and remove the stubborn residue.
Apply a chemical solvent.
Concrete chemical solvents can loosen any remaining contaminant residue. Follow the directions on your chemical stripper for proper usage. You should use a stripping solution made specifically for concrete so as not to harm the pores of the material. Apply the chemical solvent to the floor in thin, even strokes. You may want to consider using an automated spray system to ensure the chemical is applied evenly. Let sit for 1-10 hours, depending on the instructions on the bottle.
(Do not use an acid wash. Acid washes will strip away the necessary chemicals that an acid stain will need to interact with in order to color the concrete.)
The solvent has now loosened the mastic, so it’s time to “exfoliate” the residue away. Grab a rotary floor machine or grit scrubbing brush to remove the loosened glues and paint from the floor. This is the most important step, as the scrubbing clears the floor of the contaminants—even those glues that are deep-rooted in the pores of the concrete.
Our Onfloor equipment remove mastic and glues without any added elbow grease. Check them out here.
Neutralize the floor.
After you’ve scrubbed away the mastic and paints, you need to neutralize the floor. This will help pick up the gunk that was scrubbed up. This will clean and sanitize the surface of the floor to prepare for prepping.
Mix a concrete cleaner and degreaser in a large mop bucket. Pour or spray the diluted solution on the floor. Agitate with a high-speed floor machine. As an alternative, you can also spray the floor with a power washer to try to get rid of any leftover chemicals and contaminants.
Follow up with a wet vacuum and squeegee to help pull up the remaining solvent and dry the floor. Consider using an air mover to fully dry the floor in order to avoid any water or droplet stains.
Stain the floor.
Now, you’re ready to go about the staining process. Your floor is clean and contaminant-free, perfectly prepped for a gorgeous acid or water-based stain.
The Bottom Line
Clean, re-clean, and then clean again. A spotless, prepped surface is necessary for a stunning concrete stain.