Plaster ceilings are delightful characteristics of old homes. It was the preferred material for ceilings before drywall came along in the 1950s. While restoring these ceilings can keep the aesthetic value and historic integrity of a home, drywall is called on to fix many issues. There is no need to rip down the plaster and create a bigger mess when you can install the new drywall right over it. Installing drywall can save valuable time and money.
Things You'll Need
Drywall lift or “deadman”
Remove loose plaster from any holes in the ceiling. Use a utility knife to create a smooth edge. Secure sagging plaster to the lath above by using screws and plastic washers. Laths are the wood slats that run perpendicular to the joists. Thickness of the plaster varies, so be sure the screws are long enough to go through the plaster and lath.
Locate joists. If a hole is in the ceiling, use it to locate a joist, and measure the distance from the wall to the center of the joist. From this measurement, determine the location of the other joists. They are typically spaced 16 inches apart from center to center. Cut a small hole in the ceiling to locate a joist if there isn't one already. Cut a piece of drywall to fill any holes. The drywall should be the same thickness as the plaster. Use drywall screws to attach the drywall to the joists or lath. This piece doesn't have to be a perfect fit. It will be covered and serves as a support for the finished layer of drywall.
Plan drywall placement carefully. The short side needs to be screwed to a joist. Measure eight feet out from a corner to see where the drywall will end. If it doesn't end on a joist, measure from the corner to the center of the farthest joist the drywall will cover. Mark the measurement on the drywall. Place a T-square along the line, and use it as a guide to score the front of the drywall with a utility knife. Snap the waste part of the drywall away from the score line. Cut through the paper on the back and discard the waste piece.
Raise the drywall into one corner of the ceiling. You will need another person to help you with this. You will also need a "deadman." A deadman is a T-shaped support tool built from 2x4s that goes from floor to ceiling and holds the drywall in place while you install it. You can also rent a drywall lift from a local home improvement or hardware store. Drill five screws into the drywall and joist nearest the center of the panel. Repeat at each end with the screws ½ inch from all edges. The screwheads should sit slightly below the surface of the paper but not puncture the surface. Complete the row of drywall. Install the next rows in the same manner. Offset the end joints four feet so that the joints of the first row do not line up with the joints of the second row.
Fill screw dimples and joints with paper tape and joint compound. Let the compound dry, and then sand. Repeat. Prime the entire ceiling before painting.