How to Install and Tape Outside Corners with Corner Bead

Outside corners take more abuse than any other drywall joint. Door frames get bumped, furniture gets moved tight against walls, and moisture creeps in from the edges. That's why corner bead exists. It's a rigid spine that holds your corner straight and strong, and it's the one drywall detail that actually gets easier the more you do it. The technique is straightforward: stick it down, cover it, sand it, repeat. The difference between a corner that lasts twenty years and one that cracks and dents in five is patience and technique. Most people rush this step. Don't.

1. Check the corner first. Walk your eyes down the corner from ceiling to floor. Look for gaps, bows, or misalignment between the two drywall sheets. If the corner bows inward more than a quarter-inch, you'll need to shim it out first—otherwise your bead will sit proud. Use a 4-foot level to check plumb. Fill any large gaps with a fast-set joint compound before you install bead.
2. Cut bead slightly short. Measure from floor to ceiling and cut your corner bead about an inch short on each end. Tin snips work for metal bead; a utility knife scores paper bead cleanly. Cutting slightly short prevents the bead from jamming into the corner and forcing the drywall apart at floor and ceiling.
3. Embed bead in compound. Mix a small batch of setting-type joint compound (20-minute is ideal for this step). Apply a thin bed of compound—roughly a quarter-inch thick—along both sides of the corner using a 4-inch putty knife. Press the corner bead firmly into the compound, centering it on the corner. Use your knife to squeeze out excess compound from behind the bead. The bead should be fully embedded but not oozing compound everywhere.
4. Cover the bead cleanly. Once the setting compound dries (check the bag—usually 20 to 90 minutes), apply an all-purpose or lightweight joint compound over the bead using a 6-inch putty knife. Run it down the center of the corner and feather it out 3 inches on each side. Your goal is to cover the bead completely but not fill the corner. One thin, even coat is better than a thick one. Sand lightly when dry.
5. Feather wider this time. Sand the first coat lightly with 150-grit paper to remove bumps and ridges. Wipe away dust with a damp cloth. Apply the second coat with a 10-inch knife, feathering it 5 inches on each side of the corner. This coat should be slightly thicker than the first and should cover any texture left by the first pass. Let it dry completely.
6. Feather edges invisible. Sand the second coat again. Apply the third coat with a 12-inch (or wider) knife, feathering it 6 to 8 inches on each side. This coat should be so thin you almost see the knife strokes disappear into the wall. The edge should be feathered so gently that you can barely feel the transition from compound to bare drywall. Straight corners rarely need more than three coats.
7. Inspect under bright light. Once completely dry, sand with 220-grit paper. Use a sanding block and light pressure. Sand in one direction along the corner, not in circles. Wipe the dust away and look at the corner in strong light. You should see one clean, straight line with no ridges, shadows, or tool marks. If imperfections remain, spot-fill with lightweight compound and sand again.
8. Seal and paint. Prime the corner and adjacent wall with drywall primer. This seals the compound and hides compound sheen from future paint. Paint two finish coats as you would the rest of the wall. The corner should now be structurally sound and visually flush.