How to Trim a Round Corner in Drywall

Knowing how to properly finish a round corner with drywall is essential to the outcome of a home improvement project. Corners are easily noticed, and a rough or poorly finished rounded corner will catch the eye of nearly everyone. Most rooms will not have rounded corners, but if you have a room that does, there are simple products and steps to follow that make finishing it much simpler.

• 1

  Tape and seal all of the drywall joints on the ceiling and walls in the room before you tend to the rounded corners. This allows for a smoother surface for the corner trim installation and a straighter finish.

• 2

  Measure the amount of ready-formed trim you will need, using a tape measure. It is best to use full strips from the ceiling to the floor if you can, to avoid seams.

• 3

  Decide on the style of rounded drywall trim you will use. You can purchase various types, including metal, plastic and paper-faced. They are typically sold in 8-foot pieces; allow some extra in case there is an error in cutting. The plastic and paper-faced are the easiest to work with; the metal is a bit more difficult as it is not as forgiving and can show minor crimps and dings.

• 4

  Measure the length of the corner and mark that distance on the trim with a pencil. Cut the trim to size using heavy-duty scissors or tin snips (if using the metal trim). Apply a generous amount of drywall joint compound to the corners on the right and left sides of the wall. Place the trim piece over the joint compound, pushing it firmly into place. If you use the metal trim, it may have nail holes along the edges. Use small nails to hold the trim in place. You will need to be sure to sink the nail heads and cover them with a finish coat of joint compound so the nail heads do not show through when the project is finished.

• 5

  Scrape the right and left sides of the trim with the drywall taping knife, from top to bottom, pushing the trim into the joint compound and squeezing out the excess from behind the trim. Scrape the excess off the knife and into your joint compound bucket or trough. This process embeds the trim into the compound, forming a sealed corner. Allow it to dry.

• 6

  Sand the joint, checking that the walls and ceiling are smooth. Seal the drywall with a coat of drywall sealer and primer. Allow this to dry, and then paint.