How to Space 1 1/4-Inch Nails for a Plywood Subfloor

The most important aspect of laying a plywood subfloor is correctly spacing the nails in the floor. The plywood subfloor is an integral part of the flooring's foundation. An improperly nailed plywood subfloor may become loose, squeak in certain parts or even buckle and leave low spots in the floor. Most flooring materials installed over a smooth substrate require a 1/4-inch-thick plywood subfloor. This plywood flooring is nailed into the substrate beneath it with 1 1/4-inch nails.

Nail gun
1 1/4-inch nails
Ruler

Instructions

- 1
  Start nailing at the left corner of the edge of the floor opposite the door. Install a row of nails that are 6 inches apart and 3/8-inch from the panel's edge. Start the first nail 3/8-inch in from the leftmost edge of the plywood flooring panel. Continue nailing all around the perimeter of the floor.
- 2
  Return to the starting corner. Space nails over the rest of the floor in a grid-like pattern. Install each nail 6 inches apart from neighboring nails on all sides. Shift the spacing slightly, when necessary, to install the nails 3 inches from the edge of each panel.
- 3
  Go back over the floor to check the nailing depth of the subfloor. Each nail should be flush with or just below the surface of the plywood. If the nails are too deep, those low points may be visible in the flooring layer. If the nails are not driven deeply enough, the high points will show through the flooring layer. Hammer down under-driven nails and remove then re-install over-driven nails.

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