How to Level a Concrete Slab Before Flooring

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How to Level a Concrete Slab Before Flooring

This is a project that shouldn’t be too difficult to tackle. Leveling a concrete slab should be done when it’s not too cold outside or raining, since these factors wreak havoc on mixing compounds. With that said, here are some things you will need before beginning this project. Depending on whether you are starting from scratch or patching a concrete slab, you will still need the following tools (Material and tools may vary from job to job).


  • Chisel
  • Sledge hammer (small)
  • Darby
  • Trowel
  • Jointer
  • Wire Brush
  • Putty Knife
  • Edger
  • Safety Glasses
  • Kneepads
  • Hammer drill and bit paint brush
  • Bucket
  • Mixing bin
  • Dust Mask
  • Caulk Gun
  • Float
  • Tamper
  • Shovel


  • Concrete Cleaner
  • Self-leveling compound for uneven floors
  • Latex bonding agent
  • Gravel
  • Sand
  • Premix or Ready concrete mix
  • Vinyl concrete patch or (sand mix)
  • Masonry crack filler
  • Quick-setting cement
  • Material for forms (if needed)

When assessing your floors, make sure there are no cracks or pitting, since either can lead to uneven floors. The reasons for the inconsistencies may vary from floor to floor but that usually means the original batch was mixed poorly, resulting in some shifting below the concrete. If you are working with an old slab and have removed the hard wood floors, you may notice that some areas have cracked.

  • Give the room a good cleaning in order to remove any excess glue or debris left from removal of the top flooring. Trowel the small cracks with a crack sealer. It can usually be found in liquid form or as ready mix. If you have larger cracks, chisel the loose spots and widen the bottom of the groove.
  • Clean the area with a wire brush and broom. Repair larger cracks with the sand mix. It’s much stronger as an agent and will fill the groove nicely. If you are using the sand mix compound, make sure you read the instruction on the package as the amount you need to use will vary.
  • Once the patchwork of grooves, cracks and pits are addressed, wash the area with warm water and let it dry.
  • Nail strips of wood across all door openings into the room you are going to level. (these strips will keep the patching agent from accidentally pouring into another room.)
  • Mix a thin batch of leveling compound in your bin and brush it onto your clean floors like you would apply a primer before painting. If you are working on new concrete, this should only require one application; however older floors may require two coats. Again, follow the directions for mixing on the manufacturer’s package. Let this dry (1-2 Hours)
    Smooth or brush the surface to match the surrounding area.
  • If you need to set a corner due too much deterioration, then use wooden braces to shape a corner.
  • When the patch has set, remove the form and smooth the surface of the patch as necessary to match the surrounding concrete.
  • Stay off the floors for at least 12 to 24 hours.

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