How to Install Metal Flashing Around Corners

Measure the height of the corner that requires flashing. Standard height dimensions call for 8-foot ceilings or a 96-inch piece of corner bead flashing. Cut the flashing to fit the dimension using tin snips. Corner bead is metal flashing that forms a corner. Each edge extends as much as 1 1/2 inches or more on each side of the corner. You also can install a rounded corner bead instead of a straight-angled corner.

Set the flashing snugly on the corner and secure it in place by installing a nail at the top, bottom and middle on either side of the walls in the holes provided. If you want to compress the metal flashing into the drywall slightly, set the metal flashing crimping tool on the corner at the bottom, and tap its flat piece with a rubber mallet. Continue running the tool along the corner, tapping every 6 to 12 inches. You cannot use the crimping tool on rounded flashing corners.

Hammer nails into each of the holes provided. As you hammer the other side, make certain you hold the metal flashing in place securely against the wall.

Finish the corner by applying two coats of drywall compound with the drywall trowel. Let the first coat dry before applying the second coat. After the second coat has dried, lightly sand with medium-grit sandpaper. This step usually is done at the same time the drywall seams and inner corners are taped, sealed and covered with compound.