Polished concrete has a modern, sophisticated appearance, and the polishing process can improve the overall condition of the material. Your concrete mix and the pouring process are the most important factors when it comes to achieving a beautiful polished concrete floor.
Almost any structurally sound concrete floor, whether new or old, can be polished. For new floors, however, the floor should be in place at least 28 days before polishing begins to ensure adequate curing. Existing floors typically require some surface preparation before polishing. Ensure you get a concrete contractor who has experience pouring concrete suitable for polishing. An experienced contractor can usually determine a floor’s suitability.
- Evaluate the concrete.
- Determine the hardness of the concrete; whether the concrete is soft, medium or hard will allow you to fine-tune the polishing process.
- Clean the surface as you repair any cracks
- Wear protective gloves and eye goggles before handling any chemicals as you keep the area well-ventilated, too.
- Prepare a solution of warm water and household detergent, and then scrub the concrete thoroughly using that solution and a bristle brush. Rinse away any suds and let the area dry.
- For especially stubborn stains or mold, you might need to use a stronger cleanser. Hydrogen peroxide, ammonia, and TSP are standard options but do not mix these chemicals.
- Purchase specialized concrete crack filler. Follow the instructions on the package to mix the filler, and then squeeze it directly into the crack.
- Acquire a concrete grinder; you can rent it from most hardware stores.
- Wear protective gear like the dust mask, gloves, safety goggles, helmet, and earplugs before handling the grinder.
- Follow the instructions that come with your grinder to determine the proper way to attach discs and power the machine.
- Grind the concrete with the coarsest disc. If you need to remove sealer, stains, or other contaminants that wouldn’t wash off, start with a 40-grit grinding disc, if not skip directly to an 80-grit disc. The 40-grit discs are coarser than 80-grit discs; however, the exact grit sizes may vary depending on the hardness of your concrete.
- Note that these discs must be metal-bonded diamond discs. Non-diamond discs will not be hard enough to grind down the concrete.
- Pass over the entire surface with each new disc to buff away any scratches made from the previous grinding disc.
- To help solidify and densify surfaces, some contractors apply penetrating hardeners to the concrete, generally after the first step of the grinding process. These products, which can be used to new or existing floors, work by reacting chemically with the concrete to form a hard, crystalline structure. They also prevent dusting of concrete and offer extra protection from water penetration and staining.
- After your primary grinding and densifying, attach a 3000-grit disc to the grinder. Work over the entire concrete surface with this disc, moving from one corner to the diagonally opposite one if necessary.
- Vacuum any debris as much as possible after you finish grinding. Note that some concrete grinders come with their own vacuum. In these instances, use that vacuum instead of a separate shop vac.
- Buffing and Sealing
- Remove the grinding disc from your concrete grinder and attach a burnishing pad. Pass over the entire concrete surface using this pad, this should buff the concrete and make it notably smooth.
- If you do not have a burnishing pad for your concrete grinder, or if the machine does not have an appropriate setting for use with a burnishing pad, use a low-speed brush-style buffer instead.
- Apply one or two thin coats of concrete sealer; Sealers protect the concrete against grease, dirt, and other stains. Moreover, using a glossy sealer should give the polished concrete more of sheen. Choose a water-based or solvent-based concrete sealer then follow the manufacturer’s instructions when applying.
- Burnish the surface once more.
- When you finish this final pass, the concrete should look as smooth and glossy as finished stone.
- Wait at least 24 hours before use; though the exact amount of time will vary depending on the manufacturer, but it will usually be between 24 and 72 hours. Allow the final coat of sealer to completely dry before you actively use the concrete surface.
- After you wait the appropriate amount of time, the polished concrete should be finished and ready for active use.