Normal square corner beads make all the edges of your wall and window sills straight. A way to upgrade the look of your edges is to install bullnose corner beads, which will make those boring straight edges look nice and round. The best part of upgrading from a square to a bullnose corner bead is you can install the bullnose right over the existing square corner bead. With the right supplies and directions you can upgrade the look of your existing walls in no time.
Install all the bullnose corner bead adaptors at the end of all the corners. Spray the two edges of the wall where you will stick the adaptor on with the spray adhesive. The adaptor goes flush with the floor and will provide a square finish so you can install the baseboard over it. Hold the adaptor in place for 15 seconds until the glue holds it in place.
Install end caps on all outside corners that do not reach the ceiling. Spray the corner with the spray adhesive. Push the end cap in place and hold it for 15 seconds. In most homes the corner of the walls reach the ceiling, so most will not require an end cap.
Measure the distance between the end cap and the floor adaptor with the tape measure for walls with an end cap. Measure the distance between the floor adaptor and the ceiling for walls without an end cap. Cut the pieces of the bullnose corner bead with the tin snips to the proper size.
Spray the entire corner with the spray adhesive. Push the bullnose corner bead onto the corner. Make sure the corner bead is flush with the adaptor and the end cap, if it has one. Hold the corner bead for at least 15 seconds. The bullnose corner bead is now installed and ready to be covered by joint compound.