Concrete floors, once found only in warehouses or large commercial buildings, are becoming more common in homes, thanks to concrete's durability. Concrete floors don't require a large amount of maintenance but do need regular care and cleaning to retain their shine. Polishing concrete is a process much like sanding wood, which strips old concrete and leaves the new layer shiny. Concrete grinding removes pits, dust and any other imperfections flooring has developed. New concrete can also be polished.
You will need the proper equipment to polish concrete. You may buy new or used equipment, or rent it. (The equipment is quite expensive.) According to PDWorld, a website for the concrete, recycling and demolition industries, there are about 15 manufacturers of concrete polishing equipment. Equipment can be bought or rented at home stores or through a website such as http://www.concretepolishingsupply.com/.
Machines used for polishing use disks infused with diamond bits that grind down concrete to the wanted level of shine. Machines use finer and finer-grit polishing disks to smooth the floor until it has reached the shine wanted. Usually, a series of disks with progressively finer grit, finishing with with 1800 to 3500 grit, is used for floors to be considered polished, says Anne Balogh, senior editor of "Concrete Expressions" magazine and a ConcreteNetwork.com columnist. The higher the number, the finer the grit, and the higher the glossy finish of the floor.
First, coarse grits are used to get rid of minor stains, pits and other flaws. This gets the floor ready for more smoothing. This first stage may require three or four passes to ready the floor for the final polishing, depending upon the state of the concrete. Once the coarser grinding is complete, the next stage consists of a fine polishing with a polishing disk of a finer grit, 1800 to 3500 grit.
Hardeners can also be used after the first grinding step to help protect the floor from water and prevent dust.
An existing concrete floor that is wavy, porous, or in need of a lot of patching, may not be suitable for polishing. Nearly all concrete floors that aren't new will need some prep work before polishing to clean off dirt, grease or other coatings.
New concrete should set for at least 28 days before grinding, to ensure that the floor has cured properly.
There are two methods for polishing floors: wet and dry.
Using the wet method, water cools the diamond grits and gets rid of dust. Water serves as a lubricant, reduces friction and increases the life of polishing tools, especially the disks, which high temperatures could melt. The biggest disadvantage of the wet method is messiness.
Dry grinding means that the machines contain the dust and leave no mess, thanks to dust-containment equipment attached to machines.
Often a combination of these processes is used. After using dry grinding, wet polishing is used to finish the floor. However, new equipment allows the entire process to be dry because of the addition of resin-bonded disks that are able to hold up against all the friction created by dry polishing.