Installing Plywood Floors
- 1). Remove your old flooring down to the floor joists or make certain the old floor is clean and level so you can lay new plywood flooring on top of it.
- 2). Stick small pieces of tape to the walls of the room to mark where the floor joists are so you can keep track of them once you lay the floor.
- 3). Measure the room to determine the number of square feet of plywood you will need. For a square or rectangular room, simply measure the length and width of the room and multiply those two figures together. For example, a room that is 15-by-20-feet has a floor area of 300 square feet. A standard sheet of plywood is 4-by-8- feet or 32 square feet. Ten full sheets of plywood would cover 320 square feet, which would allow for normal wastage.
- 4). Break down floors that are not completely square or rectangular into sections that are. Simply figure the square footage for each square or rectangular section and then add all of the sections together.
- 5). Multiply the length times half the width of triangular sections to find their square footage. The formula for finding the area of a circle is pi times the radius of the circle squared. Pi equals 3.14.
If a triangle has a base width 10 feet and a length of 12 feet then the triangle has an area of 60 square feet . A 12-foot diameter circle is 3.14 times 36 (6 squared) or 113.09 square feet. - 6). Cut the plywood with a table saw, band saw, or skill saw to the proper sizes to fit the room. Leave as many sheets whole as possible. Cut lines as straight as possible so that edges, where boards butt up against each other, will look their best. Keep in mind, especially when measuring, that there needs to be 3/16 of an inch space between boards for proper expansion (boards expand and contract with temperature variations).
- 7). Nail the plywood to the joists using a brad nailer to make the smallest hole possible in the board. If a brad nailer is not available, use wood screws to screw the boards to the joists, counter sinking the heads of the screws, and filling in the holes later with wood putty.
- 8). Fill in the space between boards -- the expansion joint --with a silicone putty that matches the color of the plywood veneer. Allow the wood putty and the silicone putty to dry completely, as per each manufacturer's instructions.
- 9). Sand the floor with a pole sander, using 100-grit sandpaper. Only sand until the floor feel smooth and all filled nail (or screw) holes are flush and the expansion joints are flush with the surface of the floor. Sand with a shop vac and then lightly damp mop with rubbing alcohol to avoid bringing up the grain of the wood.
- 10
Sand a second time with 200-grit paper using the pole sander. Sand only until smooth. Gently use the shop vac and then gently damp mop with a well-wrung-out mop. Allow the floor to dry completely. - 11
Stain the floor if desired, using wood stain and a mop. Allow the stain to dry and then pour a dinner-plate-size puddle of floor-grade polyurethane on the floor near a corner away from the door. Use a mop to spread urethane over the entire floor (adding more dollops of urethane as needed). - 12
Allow the urethane to dry completely as per manufacturer's instructions (minimum of 24 hours) and then lightly sand with 200-grit paper using the pole sander. Wipe clean with a slightly damp mop. - 13
Add two additional coats of polyurethane, sanding between coats and damp moping. Allow the urethane to dry completely between the second and final coat. Allow the third and final coat of urethane to dry completely (at least 48 hours) before using the room.