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Sanding a concrete floor, wall, or countertop is a great way to make your concrete shine, but what’s the best way to do it? With the right tools and attention to cleanliness, sanding your concrete surfaces is a rewarding home improvement project you can show off to your visitors. We’ve put together a step-by-step guide to sanding concrete, including the exact materials you’ll need. If you’re ready to get sanding, read on!

Things You Should Know

  • Dust, wash, and fill any holes or cracks in your concrete before sanding.
  • Use an orbital sander or walk-behind sander with diamond sanding discs, or handheld diamond sanding pads.
  • Sand the concrete at least 3 times, working from coarse to fine with coarse (60-grit), medium (120-grit), and fine (200-grit) pads.
  • Dust or rinse your concrete between sandings and apply a concrete finish to preserve the surface.
1

Sand small areas by hand or use sanders for large surfaces.

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  1. Sand by hand if your concrete surface is small, has artwork you’d like to preserve, or is already fairly smooth. You’re less likely to oversand this way, and it’s easier to sand tight spaces. For big, rough surfaces, use an electric tool:
    • Use a walk-behind sander for very large surfaces like floors or driveways. They are expensive to rent, but will make your sanding job go by much faster.
    • Use a handheld orbital sander for areas like countertops, walls, concrete decor, or even floors.
    • Sand wet or dry with any tool (electric or manual). Wet sanding extends the life of your pads but takes longer. Dry sanding is faster but makes more dust.
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3

Clean the concrete.

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  1. First, vacuum or brush away loose debris (double check corners and edges). Then scrub the surface with liquid dish soap and water. [1] Rinse away the soap residue with clean water and a sponge. [2]
    • Let your concrete surface dry completely before taking further action. It may take several hours or overnight.
    • When particles get trapped under a sander, they can scratch up the surface of your concrete and cause damage while you sand.
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4

Fill any holes or cracks in the concrete.

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  1. Spread concrete patching slurry to fill holes and even the surface. [3] Pick a slurry or patch similar in color to your cement so the filled cracks aren't visible. Spread the slurry over the concrete with a trowel , pressing firmly to eliminate air pockets. Smooth out the surface so it’s level with the concrete. [4]
    • Let the slurry patch cure for 2 hours, then cover it with plastic. Sprinkle water under the plastic every day until the patch hardens (typically in 24-48 hours).
    • It’s OK if you slightly overfill a hole. Any bumps that form when the slurry dries will be sanded away later.
6

Do a rough sand with your coarsest (30- to 60-grit) pad.

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  1. Whether you’re sanding by hand or with a machine, sand your concrete surface in sections with a coarse (30- to 60-grit) pad. Sand from the corners of your sections toward the center, keeping your sander level.
    • If your electric sander can’t reach a small spot or corner, use a handheld sanding pad to smooth it out.
    • Use a long level to check that your concrete is evenly sanded before going to the next section. In small areas, set your sander down and look for gaps between the disc and the concrete.
    • If you’re sanding by hand, stroke upwards against the coarseness of the sanding pad.
    • Dry sand for this first round to remove the roughest imperfections quickly. Wait until the second sanding or beyond to wet sand if preferred.
7

Dust or wipe down your concrete between sandings.

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8

Sand twice more with 120- and 200-grit pads.

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  1. Follow the same strategy as before, working in sections across the entire surface area with your medium (80- to 120-grit) pad. When you’re done, clean the concrete again and sand once more with a fine pad (200- to 400-grit).
    • Repeat cleaning and sanding until you reach the desired smoothness, using finer sanding pads each time.
    • There’s no specific number of times you need to sand the concrete—it all depends on how smooth you want it and how rough it was to begin with.
    • If you’re wet sanding, pour water on the concrete (not the sanding pad) and sand over it. Use a consistent amount of water over each patch of concrete.
10

Seal the surface with epoxy concrete finish.

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  1. Follow the instructions on the finish—typically, you’ll apply sealant to corners and edges with a paintbrush , then cover surfaces with a roller . Allow 1-2 days for the sealant to completely dry (the concrete may look darker or wet in the meantime). [7]
    • If you’re sealing a concrete floor, make sure to start away from a door and work towards your exit so you’re not trapped.
    • Ventilate the room or space as much as possible to avoid inhaling toxic fumes.
    • For maximum safety and the best application, review all instructions about prepping the concrete and cleanup, too.

Expert Q&A

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      Things You’ll Need

      Tips

      • Consider hiring a specialty concrete company for important or difficult jobs. They'll sand and polish the concrete for you, or put an epoxy finish over it to smooth it out.
      • Always sand lightly and evenly. You can always take off more concrete with additional pressure if needed, but you can’t add it back if you take off too much.
      • It's not impossible to sand concrete with regular sandpaper, but it will take much more time and labor to get results.


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