Level Concrete Floors

Concrete floors can develop problems over time. They can settle unevenly, causing a noticeable dip in the surface, they can develop cracks that can trip you when walking across the floor and the surface can be degraded by exposure to excess moisture. This can happen in basements where the clothes washer and water heater are usually located. This damage should be repaired for safety as well as to increase the value of your home. In addition, if you want to lay a new floor of tile or hardwood, you need a level surface to work on. Leveling concrete floors is not a difficult job but it does require some body strength to lift and carry heavy bags of compound. In addition, you may need to rent some special equipment.

Steps

  1. Remove all of the furniture and appliances from the room. If there are baseboards, you should consider removing them until the floor is leveled.
  2. Use a piece of chalk to mark all obvious high spots on the floor with an "x" and any dips with an "o."
  3. Working in small sections, sweep a carpenter's level over the entire floor, marking high spots and dips with the chalk.
  4. Mix a batch of concrete repair mix according to the manufacturer's directions, and fill in any cracks or low spots deeper than � inch (0.6 cm) and allow to dry.
  5. Use a concrete grinder to grind down high spots. Wear eye protection and a face mask for this step.
    • You can rent the appropriate sized grinder for your job. If you're working in the basement, remember you have to get the grinder up and down the stairs.
  6. Clean the concrete floor thoroughly. You want to remove any trace of grease, oil, concrete chips or other solid debris and any contaminants. Allow the floor to dry.
  7. Pour primer onto your clean dry floor, and use a soft-bristle push broom to spread it over the entire surface of the floor, pushing down to get it into the pores of the concrete. Sweep of any excess puddles of primer, you want to end up with a smooth concrete surface.
  8. Allow the primer to dry to a tacky finish, which could take from 1 hour to 24 hours.
  9. Mix the self-leveling compound following manufacturer's directions. If you're working on a basement floor, buy the compound made with Portland cement rather than gypsum because Portland cement is highly impervious to water.
  10. Dump all of the self-leveling concrete mix onto the floor. Set the spreader depth to 1/4 inch (0.6 cm) and cover the entire floor. You will have about 10 minutes for this step, so make sure you don't make more compound than you can spread in that time.
  11. Use a steel smoother to run over the surface and break any tension in the concrete. This allows the compound to fill in small depressions or marks left by the spreader tines as well as assure a smoother finish with few if any pinholes.
  12. Consult manufacturer's recommendations for curing time as it depends largely on temperature and humidity.

Tips

  • To assure a level concrete surface with no bumps, make sure your leveling compound is mixed thoroughly with no lumps left in it. A heavy-duty electric drill, minimum of 650 rpm, fitted with a paddle will be of enormous help.

Warnings

  • If the concrete floor is heavily covered with contaminants, you may need to grind or sandblast the entire floor to achieve a clean, solid layer of concrete.

Things You'll Need

  • Concrete sander
  • Sandpaper
  • Eye protection
  • Face mask
  • Floor cleaner
  • Concrete repair mix
  • Concrete primer
  • Push broom
  • Concrete leveling compound
  • Water
  • Large container (for mixing leveling compound)
  • HD electric drill with paddle attachment
  • Concrete spreader
  • Concrete smoothing tool

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Sources and Citations

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