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.
If you’re sanding by hand, use handheld diamond sanding bars. Use diamond sanding discs for sanders. They typically come in sets with a range of grits. Make sure to buy the correct size for your machine. Use discs meant for wet or dry sanding to match whichever style of sander you’re using.
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.
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.
Inhaling concrete dust can cause long-term respiratory problems and other health conditions. Protect furniture and other surfaces from sanding dust with tarps or cloths.
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. [7] X Research source Dry sand for this first round to remove the roughest imperfections quickly. Wait until the second sanding or beyond to wet sand if preferred.
Frequent cleaning gives you a fresh slate to sand, plus it reduces the risk of grinding hard debris into the surface. Some dry sanders have a vacuum attachment or dust compartment to catch concrete particles while you work.
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.
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.
