Outside corner bead assures straight corners that are dent resistant. It is available in many sizes, 8 feet, 10 feet, 12 feet, etc. Obviously, the first step is buying the right size. Other than that, here's the step-by-step.
Step by step:
- Install it a couple of inches above the floor but low enough on the wall that the baseboard will cover the corner.
- Make sure the edges of the drywall forming the corner are cut cleanly and not overhanging. You can trim back minor imperfections by running a putty knife down the adjacent wall surfaces.
- Apply joint compound to both sides of the corner. It should be thick enough that you cannot see drywall paper through the mud and it should extend out from the edge enough so that the bead will fully bed into the compound.
- Bed the corner bead into the compound and gently squeeze it into the corner, keeping the center straight.
- Wipe the compound up from the bottom to remove the excess mud.
- Use a wide knife, at least six in., to check the plane of the wall moving into the corner. You should be able to see daylight between the blade and the wall on both sides of the corner bead.
- If you cannot see daylight on one side, bed the corner slightly deeper.
- Wipe the joint clean with a knife.
- After the compound dries, feather the edge using a wide knife, filling the concave daylight divot.