How to Level a Plywood Subfloor for Hardwood Flooring

By Wade Shaddy

Hardwood flooring used in homes or buildings typically has no particleboard underlay beneath, such as would be the case if tile, carpet or linoleum is installed. This is because hardwood is installed directly to the plywood subfloor. Plywood is not as flat or as uniform as particleboard underlay, so precautions should be taken to ensure that the plywood is flat and level before installing hardwood on top. Leveling a plywood subfloor is not difficult, as most of the floor joists should already be relatively level.

List of Items Needed

  • Board
  • Marker
  • Floor leveler
  • Leveler applicator
  • Sanding tools
  1. Lay a board on its edge on the plywood floor. Grab the board in one hand and sweep it across the floor. Watch the edge where the board contacts the floor. You will see where the high and low spots are as the board sweeps across.

  2. Mark all of the high and low spots. Apply floor leveler to the low spots. Smear and taper the edges of the leveler. Let the leveler dry according to the manufacturer's instructions.

  3. Sand the high spots in the plywood that you marked. Also sand places where you applied leveler. Sand over the entire floor lightly to blend the high and low spots together.

  4. Sweep the board over the floor. Repeat filling and sanding until the floor is level, if you still have high or low spots.

Tips and Warnings

  • Select the straightest board you can find to use for leveling.
  • Always wear breathing and eye protection when working with wood and leveling compounds.

© Demand Media 2011