Concrete Surface Preparation & Grinding

Remove any dirt or debris from the surface using a push broom or stiff-bristled brush. Clean the concrete after dirt removal to rid the surface of ground-in dirt, using a rope mop or sponge and a pH-neutral cleaning solution. Rinse the concrete using clean water, then wait for the concrete to dry fully.

Repair any cracks or holes in the concrete before grinding the surface. Fill concrete cracks with a thick paste of Portland cement and water, pushing the mixture firmly into the cracks with a putty knife, then scraping across the filled crack with the knife's edge to level the compound. Repair holes in the concrete with non-shrink mortar. Pack the hole with the mortar using a trowel and then level the surface with the flat of the trowel. Wait overnight to allow the repair materials enough time to harden.

Attach a grinding pad to the base of a concrete grinder. Use a handheld grinder for vertical surfaces or small areas such as steps and counters, and a floor grinder for concrete floors and slabs. There are a variety of grinding pads available. Choose one according to your desired effect, with lower-grit pads used to remove thicker layers of material from the concrete for leveling purposes and finer-grit pads used for polishing.

Connect a vacuum hose to the concrete grinder to carry away concrete dust. Move the grinder to the starting point, an area of the slab farthest from a door, or a corner of a step or counter. Turn on the vacuum, and then start the grinder.

Lower the grinding pad to the concrete surface and move the pad in a small circular motion, working in overlapping rows across the surface. By using a continuous circular motion, you avoid creating row marks in the concrete or leaving visible swirls. Keep the pressure light on the grinder, allowing the pad to do the work of removing the concrete material. Concentrate on high areas you wish to level out as you grind the surface. Stop the grinder at the end of each row and move back to the beginning point to start grinding the next row. Continue until you've gone over all of the surface once.

Switch the pad on the grinder base for one of finer grit, to create a smoother surface. You can grind an area level and then polish it to a shine by using progressively finer pads with each pass. Sweep up any concrete dust before starting the next pass with the grinder.