Concrete etching is a procedure used to prepare a floor before applying a coating. The etching product is used to open up the pores in the concrete to create a rough surface for the floor paint to adhere to when it is applied. Concrete may look solid to the naked eye, but it is a very porous substance. Finishing a concrete floor in a basement, warehouse or factory is a way to seal it to prevent substances from penetrating below the surface which can potentially cause damage.
Before starting to etch concrete, the surface must be thoroughly cleaned and allowed to dry. Before using any products on the floor, it should be swept to clear out any dust or dirt that is on the surface. Once this step has been completed, a cleaning product, such as trisodium phosphate (TSP) may be used to remove any dirt, grease, or mold that may be present.
Be sure to read the instructions on the cleaning product packaging to find out what safety precautions should be taken before using it. Rubber boots, gloves, and safety goggles should be worn. Some cleaning products recommended for concrete will cause irritation if they come into contact with exposed skin, and covering up is the safest way to proceed when using them.
Muriatic acid is the product that has traditionally been used for concrete etching, but there are other substances available that can accomplish the same goal. The product will probably need to be diluted with water. Be sure to put the water in the pail first and then add the concrete etching product to it, as opposed to starting with the etching compound. If some of the solution splashes out of the pail, it's far better to have water and a small amount of concrete etch escape than a full concentration of the concrete etch product and a bit of water.
The concrete etching solution should be spread on a small area of the floor with a long-handled brush. After 20 minutes, the solution needs to be rinsed off the floor and allowed to dry. The floor should be examined carefully afterward and if the texture still appears smooth, the process needs to be repeated until the floor has a sandpaper-like quality to it.
Concrete etching should always be performed in a well-ventilated area. Anyone who is working and starts to feel weak or dizzy should leave the location immediately. Medical attention should be sought as a precaution.