Leveling a basement floor is generally not necessary if you intend to install a sub floor. Any difference in level can be compensated for by using shims while framing. If however, you intend to install the flooring directly onto the concrete basement floor, you must make sure that the basement floor is level and in good repair.
The key to leveling the basement floor is to use a self leveling compound. This material will ensure that the floor is perfectly level, without requiring you to use a level and modify the basement floor slab after the compound has been poured.
Step 1: Remove any baseboards or other items along the perimeter of the floor using a pry bar. Sweep the basement floor thoroughly, removing any dirt and debris. Wash away any stains: they could prevent the self leveling compound from properly adhering. Wait until the floor is completely dry before proceeding.
Step 2: Use latex concrete caulk to fill in any cracks. Simply use the caulk gun to pipe the caulk into the crack, then smooth the surface with a putty knife. If there are any slight grooves or other imperfections, don’t worry, the self leveling compound will conceal them.
Step 3: Place expansion tape around the perimeter of the room. This will prevent the self leveling compound from spilling into another location and also act as an expansion joint, preventing cracking and other problems.
Step 4: Add water to the self leveling compound, paying particular attention to the manufacturer’s instructions regarding the amount of water. If possible, mix it in a wheelbarrow, which will allow you to easily maneuver the bulk of the leveling compound during the next step.
Step 5: Start adding leveling compound against one wall using a shovel. Spread leveling compound into the corners of the basement floor, using a trowel as necessary.
Step 6: Continue adding rows of leveling compound, spreading compound with a concrete rake until it is somewhat smooth. The self leveling compound should level minor perfections on its own over time. Fill the entire basement floor with leveling compound.
Step 7. Wait for the leveling compound to dry at least 72 hours before proceeding. Once completely dry, you can stain and seal the new basement floor, or add wooden flooring or tile.