Symptoms
- Corner appears wavy or not perfectly straight after a repair
- Light reflects unevenly along the corner edge
- Corner bead visible or slightly protruding on one side
Likely causes
- CommonCorner bead installed at a slight angleIf the bead wasn't held perfectly plumb during installation, the corner won't read as straight.
- CommonUneven joint compound application on one sideMore compound on one side of the corner than the other creates a visual waviness.
- PossibleOriginal framing or corner not perfectly squareSome corners were never perfectly square to begin with, especially in older homes.
What to do
- Check the corner bead itself for straightness using a level or straightedge.
- If the bead is bent or crooked, it may need to be removed and reset.
- Apply joint compound in thin, even coats on both sides of the corner.
- Use a corner taping knife to keep both sides balanced as you apply compound.
- Let each coat dry fully and sand lightly between coats.
- Sight down the corner in raking light to check for waviness before the final coat.
- Prime and paint once the corner reads straight and smooth.
Tools and parts
- Corner taping knife
- Level or straightedge
- Sandpaper
Corner beadSearch: “drywall corner bead”
When to call a pro
Call a drywall finisher if the corner still looks off after a couple of attempts, since getting corners straight takes practice.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.