Locate the main source of the leaking and stop it. You might even have to remove damaged drywall portions to identify the source in certain situations. 2. Dry the Ceiling Take two strips of furring board (thin strips of wood used to raise or level certain surfaces) six inches longer than the hole’s width. These boards can be found at home improvement stores. You can use a hand saw, or whatever power saw you have available to cut them. 4. Attach the Boards Locate the joists each side of the hole with a stud detector. Next draw a line along each joist, half-way across its width, with a straightedge and pencil. Then join them up to mark a square or rectangle around the damaged area. Step 1 Most modern ceilings are built from sheets of plasterboard nailed to the joists. These joints are taped with scrim - a very open-weave, self-adhesive tape. Wet plaster is then added, or the ceiling is finished with jointing tape and compound - which seals the joints and creates a surface ready for decorating. The floor of the room above a plasterboard ceiling may well be laid with floorboards or chipboard. Suspended ceilings This was a time-consuming method of building walls and ceilings, as individual laths (thin strips of wood) had to be nailed to the joists and then covered with layers of plaster. The plaster was squeezed between the laths so that 'nibs' formed - ridges of plaster that squeezed through the laths and set hard, holding the ceiling plaster in place. The room above would traditionally have had floorboards. Plasterboard

Drive nails into the noggins at an angle to secure them to the joists. Using plasterboard that's slightly thinner than the depth of your ceiling, cut a piece the same size as the hole. Fix it in place with plasterboard nails along the joists and noggins. Step 3 Toilet paper will readily demonstrate any reaction to wetness, helping you to focus your search. What You’ll Need Insert the strips at the ends of the hole. You want the ceiling to overlap about ¼ of the boards on the sides. Holes that exceed six or seven inches in diameter are normally considered large holes. What You’ll NeedTake an electric drill and insert drywall screws through the ceiling and overlapping boards. Do this for both ends. 5. Attach the Patch It’s crucial to identify the main leaking source before learning how to fill holes in the ceiling caused by water damage. Both, lath-and-plaster and plasterboard ceilings are fixed to the joists that support the floor above. The depth of the joists will vary depending on the age of the building (older ones are often deeper than modern ones) and their length. Lath and plaster Water can travel a startling distance from the source of the leak, and roof leaks are especially difficult to isolate. Even in seemingly straightforward situations, there are a variety of possible sources of water. I really doubt that ther would be any sort of off the shelf repair other than a circular conduit box cover of the appropriate size. That leaves two dome head screws in your ceiling

After putting on all your safety gear, cut a drywall patch that’s two inches longer (on all sides) than the hole in the ceiling. Place the patch on the ceiling, centered on the hole. Using a pencil, mark the outline of the patch. 2. Cut the Hole

Installing Shiplap Over the Ceiling