Polished concrete is strong, durable and low maintenance while having that earthy texture of stone with a polish equal to granite. Here is how it is done.
It is similar to traditional polished terrazzo which is very flat and poured as a special mix to make the finish more successful. Polished concrete floors can also look almost bumpy and have little or no aggregate showing. It should be noted that flatness and polishing are not necessarily the same thing. It’s recommended that understand this before agreeing to your project.
It costs extra time and diamond wear to cut floors with a concrete grinder until they are flat. They can either be ground flat to fully expose the aggregate like terrazzo, or the aggregate can be partially exposed, or the concrete grinding can expose no more than the fine sands at the surface. It often takes skill and experience to control the process of polished concrete floors and the quality of the concreter’s original laying work is also an element in the quality of the finish. Where the aggregate is a feature special materials can be added to the wet concrete mix such as colored pebbles, metals and glass to enhance the final appearance.
Most people are unaware that there are ten to fifteen steps for polished concrete floors which takes a long time to complete and can be quite expensive.
Typically, it takes many grinding passes to finish a highly polished floor. The rule is to double the diamond grit size under the concrete grinder for each pass so a contractor might start with very coarse, 16 or 32 grit size diamonds, then use 60 grit diamonds followed by 120, then start again with a 50 grit diamond resin pad instead of a metal segment. Using the resin pads, the steps may be 100, then 200, 400, 800, 1500 and finally 3000 grit. That would be ten separate grinding passes which does not count the two other essential steps.
After the steps above are completed, a sealant is added to the floor to protect the shine and add chemical resistance to the result. With polished concrete you can also add a color to the floor, typically done after the 400 grit resins.