How to Sand a Concrete Basement Floor

From dust and dirt to caked-on grime, your basement's concrete floor contains layers of debris and possibly layers of paint that needs removing before applying a new layer of paint or coating. Cleaning the floor with soap and water is not enough. You need to sand the concrete floor, by hand or with a sander, so the new layer of paint/coating can adhere to the concrete correctly and not just cover debris or old paint.

...
Use sandpaper and a sanding block to abrade your basement's concrete floor.

Cleaning

Step 1

Move any furnishings from the floor you plan on sanding to another room or area.

Step 2

Sweep the floor and take up the debris with a dust pan. Dispose of the debris in a trash bag or can. Wear latex gloves to keep your hands clean.

Step 3

Mix 1/8 cup of Trisodium Phosphate (TSP), 1 qt. of chlorine bleach and 1 gallon of warm water in a bucket. Stir the mixture with a mop. TSP is available at hardware and home improvement stores.

Step 4

Wring out excess mixture and mop the concrete floor thoroughly with the mop.

Step 5

Rinse the mop with warm water from a sink. Wring out excess and mop the floor with the damp mop.

Step 6

Re-dip the mop in the mixture and repeat steps 4 and 5 until the floor is clean.

Drying & Sanding

Step 1

Let the concrete floor air dry for three days. Attach a piece of 80-grit sandpaper to a sanding block or electric floor sander.

Step 2

Sand the floor by hand using the sanding block or with the electric floor sander. Work in sections and wear a face mask and safety goggles to keep the dust from sanding out of your nose and eyes.

Step 3

Change out the piece of sandpaper when it becomes smooth. For stubborn layers of paint/coating, sand the layer repeatedly with force to break up the paint or coating.

Step 4

Vacuum the floor with a shop vacuum or vacuum cleaner using the crevice attachment. Dump your vacuum cleaner frequently in a trash bag or can. Keep your face mask and safety goggles on during the vacuuming process.

Step 5

Wipe the floor with a piece of cheesecloth to remove remaining dust the vacuum cleaner didn't get up.