Polished concrete step by step: Preparation, Grinding, Polishing and Sealing.
Polished concrete has a modern and sophisticated appearance, and thanks to the polishing process it is possible to improve the performance of this building material. You will need to remove all imperfections, polish the surface until it is smooth and apply the sealer. The process is simple to understand but requires time and physical effort.
Discover all the improvements you can benefit from with a polished concrete floor in this post.
Concrete preparation or adaptation
- Evaluate the concrete. The Mohs’ test is used to determine the hardness of minerals (the concrete). In this way we will be able to determine if it is a soft, medium or hard concrete and thus to adapt our polishing process.
- Use the tools provided in the kit to compare the hardness of concrete with the hardness of other minerals. The scratching pen that is able to scratch the concrete, the previous level corresponds to the hardness of our concrete.
- Clean the surface. Normally cleaning with water and a scrubber dryer is sufficient, but you can also add a mild soap to the machine te remove stains.
- For difficult stains or mildew, you may need a stronger cleaner. Hydrogen peroxide, ammonia, and phosphate cleaner (TSP) are good choices, but do not mix these chemicals. Use only one chemical.
- Wear protective gloves and goggles before handling chemicals and keep the area ventilated.
- Repair any cracks or damages. Now is the time to repair any joint or damage on the floor.
- Use a special filler for concrete cracks. Follow the instructions on the package to mix the filler.
- Allow the filler to completely dry before moving on to the next step.
Polishing of coarse-grained concrete
- Procure a concrete grinder. You will need to use a specialized tooling to grind and polish the concrete floor.
- Please note that this can be a considerable expense depending on the size of the project. For small areas it is worth renting, but for large areas it is preferable to contract a company for polished concrete or think about buying a machine on your own.
- Wear protective equipment. Before using the grinding machine, wear a dust mask, gloves, safety goggles, and earplugs.
- Throughout the process of grinding and polishing the floor, you can use water to avoid excessive dust generation. Slurry will be generated and will need to be cleaned at each step.
- While not strictly necessary, you can also wear a helmet to protect your head in the event of an accident. This is especially important if you are working on a construction site.
- To prevent accident risk, wear security shoes with a good grip.
Polish the concrete with the lowest grit. If the floor has many imperfections or difficult stains, start with a grit of 30, if you feel that the floor is in good condition you can jump directly to grit 60 or 80.
Please note that it must be diamond impregnated discs. Other grinding tools will not be hard enough to grind the concrete.
Note that lower grains indicate rougher discs. In other words, grit 40 discs are rougher than grit 80 discs.
Follow the instructions of your grinding machine to determine the correct way to place the grinding tools. Treat the whole concrete surface, working gradually from one corner to the diagonally opposite corner.
Polish the concrete floor progressively, starting with the lowest grit and ending with the highest one.
The grit of the required grains may vary depending on the hardness of the concrete. However, as a general rule, start with grit30 and continue with grits 60 and 80. Your floor is now ready for the polishing procedure, which will be executed with resin bond discs from grit 50-3000, depending on the gloss level to be achieved.
Concrete finishing and sealing
- Apply a thin layer of concrete sealer. Choose a water-based (solvent-free) concrete sealer and follow the manufacturer’s instructions. Normally these concrete sealers should be sprayed onto the surface. What is a concrete sealer?
Our suggestion: BECOSAN® Protective Sealer
- Sealers protect concrete against grease, dirt and stains. In addition, the use of a sealer increases the gloss of a polished concrete.
- The usual concentration of concrete sealer used is 0.1 litre per square metre or 100 ml per square metre.
- Apply in a single layer. It is important to distribute the sealer with a microfiber mop, avoiding the formation of puddles. Wait between one and three hours for it to dry before moving on to the next step.
- Polish the surface once more with the finishing pads. For this step you need a high speed burnisher and diamond pads. Work slowly and covering the entire surface at a uniform pace.
- Move in the direction opposite to the direction in which the sealer was applied.
- Once finished, the floor will be smooth and shiny like glass.
Wait at least 24 hours before using the floor. Allow the sealer coat to dry completely before actively using the concrete pavement.
- The exact amount of drying time varies by manufacturer as well as ventilation and site conditions, but will generally be between 24 and 48 hours.
- After waiting for the appropriate time, the polished floor is finished and ready for active use.
Concrete polishing companies throughout the world
Remember that if after this you want to contact a concrete polishing company, we can help you, we have certified applicators throughout the world.
BECOSAN® only works with certified applicators to ensure the quality of their finishes.