How to lay plywood flooring

When building or remodelling a home, the manner in which you lay plywood flooring, also know as decking, is the same. Plywood flooring comes in different thickness and materials. OSB, orientated strand board, is a plywood mainly used for roofing, while 3/4-inch building-grade plywood is used for decking the floor joists on new construction. The installation of the decking is pretty simple.

Place the first whole sheet of plywood decking in one corner, running perpendicular to the floor joists. Check the fit of the plywood to make sure it's square to the rim joists. The rim joists are the exterior pieces of wood that surround the perimeter of the floor framing.

Apply a bead of caulking along the floor joists where the plywood will cover them. Use a caulk gun to apply the adhesive. You do not need a lot of adhesive; it will spread out under the weight of the plywood and it is very strong.

Screw the decking down to the floor joists, using 1 1/2-inch decking screws. Place the screws about 16 inches apart on every floor joist. Use a power screwdriver for this step.

Place the following full sheet of plywood along the narrow edge of the previous piece. Install the next piece of plywood in the same manner as the last one. Align the tongue and groove of each piece of plywood and use a tapping block to tighten the joint. A tapping block is a piece of 2-by-4 scrap lumber. The block protects the tongue and groove of the plywood when using a sledgehammer to tap the plywood into position.

Repeat step 2 through 4 for the remaining plywood flooring. Start the next row of plywood with a half sheet. The staggering of the end joints makes for a stronger floor system. Snap a line at the end of the plywood rows, using a chalk line. The chalk line will indicate the other end of the foundation. Cut off the ends of the plywood, using a circular saw.


Wear safety glasses when using power tools.

Things You'll Need

  • Caulk gun
  • Construction adhesive
  • Decking screws
  • Hammer
  • Block of wood
  • Circular saw
  • Chalk line
  • Square
  • Pencil
  • Power screwdriver
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About the Author

Jim Wildman served in the United States Marine Corps as a Communication Chief for 10 years. After his tour of duty in Desert Storm he attended Oklahoma State University receiving his Bachelor of Architecture. He worked as an architect for 10 years before starting his own design/build company. He began writing in 2009 for Demand Studios and published on eHow.