Polished concrete is a growing segment of decorative concrete that involves a series of “grinding” and “polishing” steps. This treatment is found on floors and cocnrete countertops. This is done with diamond grinding pads which are like round sanding pads but much more advanced and robust enabling them to cut into concrete. Concrete is polished in steps and the diamond pads have grits. One starts with the low “rough” grits(often called metals) under 100 grit and proceed with a finer grit each step. Usually the grit numbers double each step, for example; 50-100-200-400-800-1500-3000. Polishing really begins with 800 as the surface becomes ultra smooth and will begin to reflect light. The machines that work these pads can range from hand held(for countertops and edging), all the way up to something a person can ride on. Most commonly, for floors, these are heavy machines that the operator walks behind.
The polishing process may often involve the use of a penetrating chemical called a “densifier” or “hardener”. These chemicals are applied at varying stages of the polishing process and they fortify the concrete making is stronger, more stain resistant and help provide more gloss. Special colored dyes may be added along the way to provide rich or subtle colors to all or part of the surface. Polished concrete is considered a “green” construction process since it is using a material that is already in place. Polished concrete floors are considered low-maintenance, as they are more durable and easier to clean than many flooring options like tile, wood or coatings. A properly maintained polished floor may last decades compared to an epoxy floor that can provide 5-10 yrs. Polished concrete is easily maintained with the use of clean water or a mild cleaner. Though not much needs to be done, many choose to finish the surface with a concrete polish guard. These are a secondary protection that may help prevent any deep staining from spills. In addition, these can often be buffed and or burnished to bring about a renewable high gloss. Not a real sealer but it often helps provide a polished finish even when the polishing process is not brought all the way thru the final polishing steps. This is especially useful on floors that are not in good enough shape to take advantage of a full polish properly.
In the case of floors that are in poor shape, are patched in multiple places, have many cracks or vary in color, there is a solution. Polishable overlay is a thin layer of special concrete that is installed on top of the existing concrete that is able to handle the demands of polishing. It will allow the look of new polished concrete and is just as durable. Polished overlays are called for more and more since they call be colored uniformly(instead of dyes) and may even use select color aggregates for specific looks.