How to Redo a Concrete Slab

Put on the safety glasses and gloves. Clean the concrete thoroughly with a heavy-duty concrete degreaser and stripper. Apply a layer of the degreaser on the concrete surface with a paint roller. Leave it on for several minutes, but don't allow it to dry. Scrub the concrete with a stiff brush to remove embedded debris. Rinse the concrete thoroughly with water until it runs clear. You can also clean the surface with a 3,500 psi pressure washer. The goal is to remove all oil and grease from the concrete.

Mix seven parts concrete resurfacer with one part water to create a relatively thick mixture of concrete. Using a steel trowel, spread the resurfacer over damaged areas of the old concrete surface, pressing it down into cracks, holes and spalled areas. Allow the repaired areas to harden for four to six hours.

Place pieces of weatherstripping in any existing control joints to keep them from being filled with the concrete resurfacer that you apply to the entire slab. Simply press the thin strips, which are typically the same size as the control joints, down into the gaps formed by them.

Prepare the concrete resurfacer for the slab according to the manufacturer's directions. Typically, you will pour 3 1/2 quarts of water into a 5-gallon bucket, then slowly add the 40-pound bag of concrete powder to the water. Stir the mixture as you add the concrete powder, using a paddle mixer attached to an electric drill. Mix the resurfacer for about five minutes until you achieve a pourable consistency.

Wet the concrete surface thoroughly with water, then push the excess water off with an industrial squeegee. Pour the resurfacer onto the existing concrete. Spread the resurfacer with the squeegee until you cover the entire area of the slab, smoothing out the resurfacer as you move it around.

Allow the concrete resurfacer to dry for at least eight hours before walking on the slab. After eight hours, you can apply additional layers of concrete resurfacer, if desired. After the resurfacer has dried completely, remove the weatherstripping from the control joints to complete the project.