Polishing cement countertops, newly poured cement countertops, first make sure the cement has fully cured. Usually a curing period of at least 28 days (at ideal temperature and humidity) is required, which is the key to achieving optimal strength and avoiding cracking. Even if the surface feels dry, the inside may not be fully cured.
Please clean the countertop thoroughly! Remove all oil stains, dirt, old coatings or wax. Then make sure the surface is completely dry.
Tool needed for polishing cement countertops
- Angle grinder: The best choice is a handheld electric motor. For small areas or edges, you need to use a handheld sandpaper block.
- Diamond grinding disc/wheel: Electroplated diamond louvre, diamond hand-rubbed grinding disc, or sandpaper
- Coarse grinding: 50-100 mesh (for coarse grinding, removing excess material from the countertop, and repairing uneven areas)
- Medium grinding: 200-400 mesh (for eliminating coarse grinding scratches)
- Grinding: 400-800 mesh (for a smooth surface)
- Fine grinding: 1500-3000 mesh (fine grinding, the surface brightness reaches a mirror effect)
Cement countertop polishing
- Place the grinder flat on the countertop and move slowly and evenly, maintaining steady pressure to avoid staying in one area for too long and causing dents. Use overlapping paths to ensure that the entire surface is covered. Pay attention to edges and corners, which may require manual grinding.
- Gradually increase the grit: Follow the order of the grinding disc grit: #50> #100> #200> #400> #800> #1500> #3000
- The finer the grit, the faster the machine can move and the lighter the pressure. This will give you a better polishing effect.
- Be patient with polishing! After each polishing, shine a strong flashlight at an angle to check for scratches. Check that the scratches from the previous process have been completely eliminated.
- After completing the highest grit polish, clean it very thoroughly:
Seal the cement cpuntertop
For high gloss and extreme stain resistance (especially in the kitchen), a film-forming sealant is the first choice. For a natural matte/satin effect and easy maintenance/repair, a penetrating sealant is better.
Always read the product description and choose a product that is suitable for cement countertops and meets your needs (gloss, stain resistance, food contact safety).
Applying Sealant
Read Instructions: Follow the instructions for your chosen sealer product carefully, including mixing ratios (if needed), environmental requirements (temperature, humidity), application method, and drying time.
Use a dedicated applicator and be sure to apply thin, even coats. Avoid runny or pooling, especially around edges. Ensure even coverage. Two to three coats are usually required, and very fine sanding (such as light swipes with 400-600 grit sandpaper) may be required between coats to remove air bubbles or dust spots and to ensure adhesion (follow product instructions). Applying thin coats is key! Thick coats are more likely to cause problems.
Maintaining Polished Cement Countertops
Allow the sealer to cure completely according to product instructions. This usually takes 24-72 hours or even longer to reach its initial hardness.
Before it is fully cured (usually 7-30 days to reach full strength), be careful when using it: Avoid placing heavy or sharp objects. Avoid contact with water or other liquids; avoid hot objects
