How to Sand a Concrete Porch

Remove all items from the concrete porch. Cover nearby plants and flowers with dropcloths to protect them from an excessive amount of concrete dust.

Sweep the concrete porch to remove dirt, small particulates and dust, using a push broom.

Attach a coarse, metal mesh diamond disc to the orbital floor grinder/sander machine. Turn the machine on and pass the orbital over the concrete porch, using side-to-side motions. Continue to pass the orbital over the porch concrete to remove all bumps, hairline cracks, imperfections and to smooth the surface of the concrete to your liking.

Vacuum the concrete dust created by the orbital machine with a shop vacuum.

Turn the orbital machine off and replace the first diamond disc with a finer, 300-grit polishing disc. Turn the orbital machine back on and smooth the surface. Use the 300-grit diamond disc to remove any leftover surface stains and/or bumps and imperfections.

Vacuum the concrete dust with the shop vacuum.

Replace the 300-grit diamond disc with an even finer 800-grit disc. Sand the concrete porch with the diamond disc until the surface of the concrete porch is smooth and free from imperfections, bumps and surface stains.

Vacuum the concrete dust with the shop vacuum.

Rinse the concrete porch, using a power washer to remove all concrete dust. Allow the concrete to dry overnight, up to 48 hours for colder areas.

Roll an even coating of penetrating concrete sealer onto the surface of the dried porch, using a long-handled paint roller. Use long, even strokes when rolling the sealer onto the concrete for a consistent finish. Allow the sealer coating to dry according to the timeline on the label.

Apply a second coat of penetrating sealer to the concrete porch after the first coat has thoroughly dried. Allow the second coat of sealer to dry before moving anything back onto the concrete porch.