How to Install a Wood Flooring Subfloor

Plywood is a common subfloor material.

When building your home, it is important to install a solid wood subfloor. All the walls, floors and cabinets are built upon the subfloor. Further, the subfloor must be installed correctly to prevent annoying squeaks. The do-it-yourself handyman can install a subfloor that will stand the test of time with a few woodworking tools and help from a friend.

Things You'll Need

• Construction adhesive
• Caulk gun
• Screw gun
• 2-inch deck screws
• Scrap piece of 2-by-4 wood stud
• 5-lb. sledgehammer
• Circular saw
• 30-lb. felt paper

Instructions

1. Apply a bead of construction adhesive to the top of the floor and rim joist where the first sheet of 4-by-8-foot subfloor will be installed. Set the subfloor carefully over the construction adhesive and align it with the outside edge of the rim boards. Place the groove side of the subfloor to the outside edge along the rim joist. This will ensure that it is square to the foundation. The construction adhesive and screws guard against squeaks. Apply the construction adhesive with a caulk gun.

2. Screw the subfloor down to the floor and rim joist with 2-inch deck wood screws. Place a screw along every floor and rim joist 16 inches apart. Use a power screw gun so that the screw heads are flush with the surface of the plywood.

3. Apply construction adhesive for the next piece of subfloor in the same manner. Use a scrap piece of plywood and a 5-lb. sledgehammer to tap the tongue and groove of the subfloor together. This is best done with one person standing on the end of the board watching the joint and the other standing on the other side tapping the 2-by-4 against the subfloor to get a tight fit. The 2-by-4 protects the groove of the plywood so the next piece can fit into it. Cut the subfloor with a circular saw.

4. Lay more pieces of subfloor. Start every other row with 1/2 sheet of plywood. This ensures that no two rows have end joints that line up with each other, forming a stronger subfloor. Install 30-lb. felt paper over the subfloor when you are ready to install the wood flooring.

Tips & Warnings

• Going from good to better and best, wood subfloors are made of 3/4-inch orientated strand board, 3/4-inch plywood or 1 1/4-inch plywood. Decide what is in your budget and pick the one best for you. Plywood subfloors will run perpendicular to the floor joist below.

• Wear knee pads to protect your knees.

• Wear safety glasses when using power tools.

References

• Hardwood Installer: Proper Subfloors for Hardwood Flooring
• Ask the Builder: Getting a New Hardwood Floor Level
• Online Tips: Wood Subfloor Problems