Corners are an important part of any building project. You'll find two-way corners at doorways without wood trim and the inside corners of soffits. The outside corner of a soffit is a typical location for a three-way corner.
No matter where they're located, it's a good idea to invest some extra care into the creation of these corners. A sloppy installation will raise the degree of difficulty in applying the drywall compound and can result in a misshapen corner that acts like a magnet for a visitor's eyes. But a carefully fitted corner will make mudding an easy task, and you'll be rewarded with crisp lines that generate compliments for your workmanship.
Bullnose corners are even easier than square profiles because you can purchase vinyl and metal corner caps. You fit the caps first, then simply make square cuts at the ends of straight runs of bullnose stock to butt them into the preformed corners. It's a good idea to purchase the corners and bullnose stock from a single supplier to ensure that the radii are equal.
Project time depends upon the amount of bead that's required and the number of corners that must be fitted, but plan on spending 15 minutes on the first bullnose strip.
Before you install strips of metal corner bead at a corner, make a mitering nip at the end of each piece using tin snips. The miters don't have to fit perfectly; you simply want to avoid overlap.
Nail the first strip into position, driving ringshank nails right through the metal. Hammer squarely to avoid twisting the metal. Carefully position the second piece of corner bead to ensure that its tip neatly continues the line around the corner.
If you build a soffit, you may have to deal with a three-way corner. After you cover the framing with drywall, double-miter a piece of corner bead for the long horizontal run, and nail it in place. Cut a double miter on another piece of bead, and then square-cut it to length for the other horizontal run. Match the tips of the two pieces as closely as possible.
For the third piece, double-miter another piece for the vertical corner. Again, carefully fit its tip against the two that are already in position. After the third piece is in place, you may need to file the tips to correct any small misalignment. Finally, take a few file strokes across the point, slightly blunting it so that it's not dangerously sharp.
If you'd like to build a soffit with bullnose edges but are unsure how to tackle the three-way corners, the quick and effective solution is a three-way cap. Choose from metal or vinyl, and between 3/4- and 1-1/2-inch sizes. Take your time when you install the bullnose beads and cap to get a snug fit between the trim pieces and so that the lines are true and square.
You can purchase a cap for an off-angle corner so you don't have to be limited to soffits and other constructions with square ends where they meet the walls. Instead, utilize a 135-degree end to make a gentler transition. At a drywall contractor's supply, you'll find these caps in metal and vinyl, and you can choose between bullnose radii of 3/4 and 1-1/2 inch.
It's possible to miter bullnose corner bead, but you'd probably have a tough time getting the joint to align precisely. Skip the problem and get better results by purchasing two-way corner caps. The one shown is vinyl, but they are also manufactured in metal. You simply nail these caps into corners and connect them with square-cut lengths of bullnose bead. Some sample installation sites include door and window frames, closets, passageways, and skylights.
Bullnose corners can require substantial amounts of drywall compound to blend the bead into the walls. Avoid problems by choosing setting-type compound for the first coat or two, and resist the urge to apply it too thickly. Instead of saving time, a too-heavy application strategy can backfire by cracking. To ensure that the crack won't telegraph through the final application, cover it with fiberglass or paper tape before applying the next coat of compound.