Concrete polishing is the act of changing an existing concrete surface by means of a mechanical process that involves cutting and/or refining the surface to a desired finish. Polished concrete is one of many end results in what is the processing of the concrete surface by mechanical refinement through the use of multiple abrasives measured in grits.
The process of grinding, honing and polishing concrete is more technical than most realize. There are many pre-existing variables that can affect the end results of the process performed. Some of these variables are within the contractor’s control, such as the quality of your equipment and abrasives and the motion and speed at which you operate your equipment. Others are beyond a contractor’s control, such as levelness and flatness of the floor or the concrete mix design used. Knowing how to contend with these variables is the difference between a craftsman who is detailed and results-oriented and a contractor who simply goes through the motions.
One of the main variables on a polishing job is the concrete itself. Residential concrete is generally a low PSI concrete mix (2,500 psi and under) that has been hand troweled. Lower PSI concrete does not polish as well because the surface is not as dense and hand troweling leaves the surface with lots of highs and lows. On the other hand, commercial concrete is a higher PSI concrete mix (3,500 psi and up) that is machine troweled in the open areas and hand troweled in the corners and tight areas. Higher PSI concrete polishes better because it is denser and the surface does not have many highs and lows.