Cover ceiling cracks with a second drywall layer.
Impact, moisture or structural settling can wreak havoc on your home's walls and ceilings. When the damage results in a cracked ceiling, you can try filling the cracks, replacing the original drywall or adding a second layer of drywall over the cracked layer. USG Corporation manufactures Sheetrock, a brand of drywall paneling that is widely available in the United States. Adding a second layer is similar to installing an original layer, but you'll have to prepare the existing ceiling before adding the new panels.
Instructions
Prepare the Ceiling
1. Tighten the old ceiling to the joists by locating the ceiling joists with a stud finder and popping chalk lines over the centers of every joist. Insert drywall screws along the chalk lines, every 2 feet.
2. Scrape away loose and crumbling bits of old drywall and joint compound from the cracks and seams with a putty knife.
3. Countersink screws or nails that might have worked loose and now protrude from the ceiling.
Install the New Layer
4. Position a new Sheetrock panel at one corner of the ceiling, perpendicular to the joists. Use a drywall hoist to lift and hold the panel. Drywall panels are 4 feet wide and come in various lengths. The edge of the panel should be located in the exact center of a ceiling joist. Use the chalk lines as guides.
5. Secure the new panel to the ceiling joists by inserting drywall screws that are a minimum of 1 inch longer than the thickness of the ceiling. For example, if the old drywall and the new drywall panels are both 1/2 inch thick, that gives your ceiling a total thickness of 1 inch. In that case, you would use drywall screws that are at least 2 inches long.
6. Insert the screws, with a drywall screwgun, every 8 inches along the seams and 1/2 inch from the edge of the drywall panel.
7. Install the next Sheetrock panel, butting it tightly to the first. Because ceiling joists sit on 16-inch or 24-inch centers, the drywall panels should fit from joist to joist. When you reach the end of the ceiling, measure and cut a new panel to fit the space.
8. Continue adding panels until the new layer is in place.
Tape and Finish the Ceiling
9. Apply self-adhesive mesh drywall tape over the seams, but do not overlap the tape where the joints meet.
10. Spread joint compound over the taped seams, using enough pressure to push the compound through the holes in the mesh tape. A 5-inch or 6-inch taping knife works well for this step.
11. Smooth out the wet joint compound with a wider taping knife over the seams. A 10-inch to 12-inch knife is sufficient. Let the compound dry completely.
12. Sand the dried seams in the ceiling with a drywall sander on an extension pole.
13. Add at least two more joint compound applications the same way you applied the first.
Tags: ceiling joists, joint compound, chalk lines, drywall screws, adding panels, drywall panels