Polished concrete looks very similar to a beautiful marble or granite floor. In order to produce the perfect polished concrete finish, you have to use a heavy-duty specialist polishing machine that employs diamond-impregnated abrasives that grind the surface down. You use finer diamond grit for each pass over the floor until you reach the level of smoothness and polish that you wish to achieve.
The floor can be finished to a level of shine that is like a mirror. As far as design is concerned, your choices are virtually limitless, the only proviso being the level of creativity of the designer. Aggregates can be embedded into the surface of the concrete before polishing giving some amazing pattern possibilities, or you can cut the surface with saw cuts to create any sort of pattern you desire. You can also use any colour that you wish, and this can be mixed into the concrete of a new floor or coloured over the surface of an existing one. You can also control the level of reflectivity depending on how fine a diamond grit you use for the final polish. Polished concrete is ideal for commercial buildings because maintenance is absolutely minimal. All you need to do is dust and give them an occasional mop over with a damp mop.
The Polishing Process
Before polishing begins, it is necessary to establish the hardness of the concrete with a MOHS test kit. This is required so that you can determine the appropriate diamond abrasives for the surface. You start with a high number thickness and scratch the surface with the tip of the tool. Normally you use a number nine tip. If that scratches the surface you try a number eight, and so on until you reach a point where the tool does not scratch the surface, and that determines the hardness of the concrete. You need to test at least three areas of the floor to get an average rating on the MOHS scale.
Next you need to prepare the surface of the concrete. The floor coating must be determined and removed with the right tools. After this is done, any cracks or holes in the surface must be repaired and filled. This is done by grinding the surface with 16, 30/40, or 70/80 grit metal bond tooling to achieve the required exposure and floor flatness.
After this point, you use grit transitional tooling to remove any scratches and then vacuum the floor. A densifier is then added to the concrete to help solidify the surface. The densifier must not be allowed to puddle because it can cause a stain. This process helps to protect the surface from dirt or oil stains and from water penetration.
Only now can you begin polishing the concrete using the right level of grit – 200, 400, 800, 1,500, or 3,000 grit. Dust must be removed after each pass, and after reaching the final grit level the floor can be burnished with a 300 grit burnishing pad.
Once you have achieved the level of shine that you wish, you can protect the surface with a commercial stain protection product. Use a surface wear protector if the surface is likely to be exposed to oils, grease, or chemicals. Apply two thin light coats using a pump sprayer and allow 30 minutes drying time between the coats. Finally, burnish the floor once again.