Cracks that appear on drywall can easily be repaired over a day or two. What you need for this repair is a mud pan, a dusk mask, painters tape, a utility knife, a 6-inch knife, a 12-inch taping knife, paper drywall tape, pre-mixed joint compound and setting-type compound.
- Prepare the wall
Cut a V-shaped notch through the full length of the crack to remove all loose wall material. This cut should be about 1/8- to 1/4-inch deep. If the crack is more than 1/4-inch deep, clean the loose material, and use a quick-setting crack filler to build the area level with the wall. Be sure to protect woodwork with masking tape.
- Lay the tape
Embed the paper tape in joint compound using the 6-inch taping knife. Moisten the paper tape with water to avoid trapping air bubbles, and lay it over the crack. Squeeze out excess compound with the knife. Apply an additional layer of compound, and feather it off about 2 inches on both sides of the tape. Let the compound dry completely before proceeding.
- Finish the seal
Apply a second, and if necessary, a third coat of compound. Use long, continuous strokes with the 12-inch taping knife to smooth the compound to a thin, even layer about 6 to 7 inches on both sides. Allow the compound to dry thoroughly before sanding it smooth and painting it. Be sure to avoid exposing the tape when sanding.