How to Install Base Molding on Bullnose Corners

In carpentry, bullnose refers to an irregular corner, either rounded or angular.

The shape of a bull's nose, very flat across the front, gives bullnose corner moldings their name.The shape of a bull's nose, very flat across the front, gives bullnose corner moldings their name.
Trim a bullnose corner with a pre-made bullnose corner board that fits on the corner on top of the outside base moldings, or cut your own to create a flat center piece, like a bull nose. Pre-made bullnose corners fit over top of rounded corner bead, commonly used to create round corners. The pre-made corner board stands out from the rest of the molding. Create a flatter bullnose by cutting your own molding pieces to fit around the curve.

Work from left to right to install baseboard. At the bullnose corner, press a piece of base molding tight against the last piece of installed base molding. Using a carpenter's pencil, mark the base molding at the outer edge of the rounded corner to get the length of board needed.

Put on your protective glasses. Set your miter saw to a 22.5-degree angle and place the base molding top side up against the saw guard. Test the precision of placement by lowering the saw blade onto the mark made in the previous step. Make any necessary adjustments.

Turn on the saw and lower the blade smoothly into the base molding and cut. This is your left-side molding piece. Using finishing nails, install this piece of molding onto the wall.

Cut a right-side piece of molding. Turn a second piece of base molding top side down to create an angle opposite from the first one. Fit this piece of base molding against the wall on the other side of the rounded corner. Use a level to make certain both the left and right baseboards extend precisely to the edge of the corner.

Install the right-side base molding to the wall with finishing nails. If possible, place nails in grooves or indentions.

Measure the distance between the outer edges of the right- and left-side moldings.

Press a piece of base molding against the saw guard, top side up, and cut a 22.5-degree angle. Measure from the outside edge of the angle to the length of the measurement taken in the previous step.

Turn molding top side down and cut a 22.5-degree angle, with the outermost edge at the mark made in the previous step.

Use adhesive or finishing nails to install the bullnose to the corner. The bullnose molding should fit snugly against the two pieces of side molding and should lightly touch the curve or angle of the bullnose wall.

Caulk to fill cracks in the bullnose corner. Counter sink finishing nails and putty. Lightly sand dried putty to create a smooth, even surface.

Things You Will Need

  • Carpenter's pencil
  • Measuring tape
  • Base molding
  • Safety glasses
  • Miter saw
  • Finish nails
  • Hammer
  • Small carpenter's level
  • Caulk and caulking gun
  • Sandpaper


  • Practice your bullnose corner on scrap pieces of base molding before cutting your good molding.

About the Author

For Judy Kilpatrick, gardening is the best mental health therapy of all. Combining her interests in both of these fields, Kilpatrick is a professional flower grower and a practicing, licensed mental health therapist. A graduate of East Carolina University, Kilpatrick writes for national and regional publications.