If your concrete garage floor is not looking as pristine as it could, you may wonder what can be done to restore the surface appearance that it had when it was new. The first thing that you will want to do is remove any oil or other stains from the floor and also clean the entire surface well with a concrete cleanser and water. Once the concrete has dried completely, you can choose either to grind the concrete to reveal a new layer of concrete or use a skim-coat of new concrete to cover the old.
Cover your nose and mouth with a respirator to prevent breathing in small particles of concrete. Purchase or rent a concrete grinder that it suited to the size of your garage floor.
Choose one corner in which to begin. Install a 1300-grit diamond grinding disc into the grinder. Turn the grinder on; choose a speed that you can control well, or you will end up with an uneven floor.
Grind the floor in straight lines. Replace the 1300-grit disc if it becomes worn out so that the grind consistency remains even.
Exchange the 1300-grit disc for an 1800-grit disc once the entire floor has been ground. Grind the floor a second time with the finer disc. Work again in straight lines, and remember to change out the disc if it wears out.
Sweep up all the dust and debris. Choose a super-fine-grit disc, such as a 3200-grit, to apply a final polish to the garage floor. Place the disc into the grinder, and grind the floor again.
Pour liquid concrete bonding agent into a paint pan and use a long-handled paint roller to apply the bonding agent to prevent bending over. Cover 10 square feet of floor at a time. Apply the concrete bond in long, straight lines, working toward an exit.
Wait approximately 15 minutes for the concrete bond to set up. Touch the surface lightly to ensure that it is tacky. Wear shoes with clean soles and knee pads to keep your knees from sticking to the floor.
Mix the concrete with the required amount of water in a plastic bucket. Stir the concrete with a shovel until the consistency reminds you of toothpaste. Carry the bucket to the first prepared section of floor.
Use a flat metal trowel to cover the floor with a thin layer of concrete. Keep the concrete about 3/8-inch thick. Smooth the surface of the concrete with the trowel; cover the rest of the floor with concrete bond and concrete, blending the edges of each section together with the trowel.
Let the concrete dry, or cure, for five to seven days before walking on the garage floor or parking your car in the garage.