How to Install a Plastic Corner Cap in Drywall

Use the tape measure to measure the height of the wall where the corner bead will be installed.

Measure the corner bead and mark the spot where you'll need to cut the corner bead, then cut it to the proper length with the scissors.

Place the corner bead on the outside corner and push it so it is snugly up against the wall. The corners of the drywall should be firmly touching the inside edge of the corner bead.

Hold the corner bead in place with one hand, or have someone else help, then screw the corner bead in place with the drill. Work your way from top to bottom and use one screw approximately every two feet. Be careful to drive the screws in straight, because if you drive them in at an angle, the screw heads will stick out of the wall and make it difficult to get a smooth, even finish when you apply the joint compound.

Apply a generous coat of joint compound to each side of the corner bead with the 4-inch drywall knife. Once the compound is applied, place the 4-inch drywall knife so one edge of it rests on the corner bead and the other side is on the wall, then pull the knife down toward the floor to smooth out the compound. Do this on each side of the corner bead and allow it to dry.

Scrape off any dried, chunky bits of compound on the corner bead by running the 4-inch drywall knife along it.

Apply another coat of drywall compound, this time working your way a few inches further out on the wall from the corner. Run the 10-inch drywall knife along the corner bead to smooth it out, using the same technique used with the 4-inch knife. Allow the compound to dry.

Scrape off any chunky bits of compound on the corner bead by running the 10-inch drywall knife along it.

Apply a final coat of drywall compound, this time using the 14-inch drywall knife,which allows you to further taper the compound and have a seamless finish. Allow the drywall compound to dry.

Lightly sand the area with the fine-grit drywall sanding sponge to smooth out any imperfections in the wall. Be careful to not apply too much pressure, which can cause grooves to form in the wall.