Preparation is especially important when the surface to be painted is a concrete floor, such as in a laundry room or workshop. First you will want to repair any cracks or holes. You will next need to prepare the concrete with a muriatic acid solution. This process is called “etching.” It’s similar to etching glass— scraping off a bit of the top so that the paint has something to adhere to. Caution: muriatic acid is strong enough to burn skin and eyes. Before you begin the etching process, put on the proper safety gear. If you can’t ventilate the work area, wear a dual-cartridge respirator.
How to prepare and paint a concrete floor:
1. First, sweep and scrape off the dirt from the floor. Clean off any grease, oil, and other contaminants using a cleaning solution.
2. Rinse the floor well to remove all traces of the cleaning solution.
3. Mix the solution to etch the floor by adding 1 part muriatic acid to 3 parts water. Do it in this order—do NOT add the water to the acid.
4. Apply the solution, using 1 gallon per 100 square feet, and scrub the floor with a stiff-bristled brush. Leave the solution on the floor until it stops bubbling.
5. Rinse the floor thoroughly with clean water. Wipe it down with a damp sponge mop to eliminate puddles.
6. If the floor isn’t dry in four hours, repeat the rinsing procedure.
7. After the floor is completely dry vacuum it to remove any powder residue left by the muriatic acid solution.
8. You can now paint the floor with an alkyd or urethane latex floor and deck enamel. It is best to paint with a roller and long pole. First paint the edges then work from the wall farthest from the door back toward the door.