DIY Drywall Finishing with Metal Corner Bead

This page contains drywall finishing instructions for outside corners, using metal corner bead. To finish outside corners with paper corner bead see this link. See these links to finish inside drywall corners and drywall butt joints and go here for more about drywall finishing materials and techniques.

About Drywall Corner Bead

Outside drywall corners can be finished with either metal or paper drywall corner bead. Metal corner bead is the easiest to install and the best choice for durability and a perfectly square corner. A slightly irregular corner formed by the drywall sheets is more easily covered with metal corner bead because the bead forms the wall corner. Some paper corner bead requires the drywall sheets come together to form a perfect square to support the bead and form the corner.

Choosing Joint Compound

For a more durable corner you can use a first coat of setting-type joint compound or mud to install metal corner bead but work quickly to be sure it doesn't set before you're done. Ready–mixed joint compound can be used for the second and finish coats. It will also work for the first coat but it's much softer, takes much longer to dry and will shrink when used in a thick application like this. See Drywall Finishing Materials and Techniques for more information about drywall finishing tools, tapes and joint compounds.

Cut the Corner Bead

Cut a piece of metal drywall corner bead the length of each outside wall corner. Use a pair of tin snips or scissors to cut from each side of the metal and then bend the bead in the middle to break it apart.

Attach the Bead with Screws

Hold the bead against the corner, pressing with a palm to flatten it tightly to both walls. Hold the bead tightly and drive a 1 5|8, or longer drywall screw through the bead and into the framing. Drive a screw into the opposite wall, at about the same level, to hold the bead in place. Move along the length of the bead pressing at each point and driving the screws at about 12 inch intervals along both walls.

Sink the Screw Heads

Sink the heads of the screws deep enough to slightly kink the metal and make a small depression in the drywall. If the screws are not driven far enough below the surface of the wall, the heads will show through the mud.

Coat the Corner with Mud

Use a 6 inch drywall joint knife to apply a thick coat of mud in crossing strokes along both walls, from one end of the bead to the other.

Skim One Wall

Skim the excess mud from the corner, resting one side of the knife blade on the bead peak and the other against the drywall. Skim off the excess mud, keeping the knife straight as it rides along the bead. Don't push too hard on the blade to avoid bending it and causing a dip in the finish.

Skim the Other Wall

Skim the other wall in the same way. Clean the mud off the joint knife frequently as you skim out the corner to avoid buildup. When you finish, go back to the start and run the clean blade along the whole length of each wall, from one end to the other, in one smooth stroke.

Skim the Edges

Skim along the edges of the mud coat to remove any buildup there, before moving on.

Scrape the Peak

Scrape any mud off the peak of the corner bead and let the application set.

Apply a Second Coat of Mud

When the mud is completely hard, use a larger joint knife to apply a second coat of mud. Use ready–mixed joint compound to apply a second, thick coat of mud over the corner to completely cover the first application.

Skim the Second Coat of Mud

Skim the excess mud from one wall at a time and then go over the whole length of both walls with a clean blade to smooth out the finish. Let the mud dry for about 24 hours and then sand it lightly with medium grit sandpaper. Use light pressure along the edges of the mud to avoid tearing into the drywall paper.