How to Change Plywood in the Bathroom

Rip out the existing plywood with a pry bar. Find a wall seam, pound the pry bar’s edge under the seam by tapping the end with a hammer. Loosen the entire seam, and then pull the plywood off. If it does not come easily, saw it off with a rotary saw, and then pull off any remaining pieces.

Remove the nails left behind with the back of your hammer. Go over the wall joists. If you find any nails, take them out. Keep a small bucket handy to keep the nails in one place.

Cut the greenboard to fit the wall with a utility knife. Measure the wall and determine if you need to make any cuts on the panel. If you do, score the greenboard's back surface with a utility knife. Pick up the panel, hold it over your knee and snap it over the scored line. Trim away the paper with your utility knife.

Hang the greenboard with drywall screws and a cordless screwdriver. Line up the panel over the wall studs. Insert one screw at the stud’s bottom and work upwards. Place one screw every 12 inches on each stud. Continue until all the greenboard is hung.

Tape off the seams with self-adhesive drywall tape. Do not use mesh tape, as it cracks a humid environment. Press the tape firmly into the panels.

Apply joint compound over the seams and screw dimples. Work with a very thin coat -- no more than one-quarter inch thick. If you use too much compound, it looks messy and eventually begins crumbling. This may mean using more than one coat of compound. Scrape on the first coat with a drywall knife. Let it set for at least four to six hours. If you need more compound, apply another thin layer and let that set.

Sand the compound until it is flush with the board. Use a fine-grit sanding block to get a good surface. These blocks are easier on the hands and you get a uniform appearance.

Prime and paint the greenboard with oil-based latex primer and paint. Finish the greenboard in the paint color of your choice. Primer helps the paint adhere to the greenboard.