To remove a plywood subfloor, remove the top layer of flooring, pry up the plywood panels, and flatten broken floor joist nails with a hammer. This process takes several hours. The required supplies are a pry bar, a hammer, goggles, gloves and a reciprocating saw.
- Remove the existing flooring
Put on work gloves, remove the top level of flooring, and discard it.
- Locate the joists
Inspect the subfloor, and look for parallel rows of nails, which indicate the location of the floor joists.
- Pry up the first board
Insert the tip of the pry bar at the juncture of two plywood panels over a joist. Drive the bar between the panels by striking it with the hammer. When the panels begin to separate, drive the pry bar further underneath one of them, and push the bar down until part of the board rips free. Hold that section of the board up with your free hand, remove the pry bar, and reinsert it at the edge of the raised section. Release the board, press down on the pry bar, and repeat until the entire panel separates from the joist.
- Make the work board
Lay the loose panel on the subfloor, and remove all of the nails. Lay the panel back over the joist, and stand on it as you pry up the next panel. Remove the rest of the subfloor with the same technique you used on the first panel. Move the work board around the room as you work.
- Remove stubborn nails with a reciprocating saw
If you encounter stubborn nails and cannot remove them with the pry bar, cut them in half with a reciprocating saw. Remove the plywood panel, and hammer the protruding nail halves into the joist.