If you are confronted with the need to perform some ceiling drywall repair, the good news is that you do it in the same way as if you were repairing a wall. The bad news is that you will have to be constantly reaching up and over your head to do it. After a bit, this will tire out both your arms and your neck. Depending on the size of the repair, you might need supports. If the repair job just requires a small patch, supports are not necessary, but it would help to have a platform on which to sit. The process of ceiling drywall repair involves several steps, but first it’s helpful to know why it requires repair in the first place.
Why Ceiling Drywall Needs Repair
Perhaps the most common cause of damaged drywall on a ceiling is a leak from a toilet, sink or plumbing fixture directly above it. As water slowly or quickly leaks onto the floor, it will seek the path of least resistance which is usually a gap through which it can flow downhill. It is only a matter of time before the water makes its way through the floor joists and starts to soak into the drywall below. Another reason it may have to be replaced is simply old age. No wall or ceiling material lasts forever. It may just be time to replace the drywall. In this case you will be replacing full sheets, so you will need support. In the former case, once you get the leak taken care of, the repair may only consist of a small patch of rotted drywall or two.
Ceiling Drywall Repair
When patching drywall, you have to first cut out the section, replace it with a fresh piece and finish it. That’s the simple breakdown of the repair. Each step is a bit more complicated. Determine the extent of the rot and trace around it with a pencil in its approximate shape. Next, locate the nearest floor joists to either side of it that run beyond the rot by at least 4 inches on a side. Mark these at the middle so they are exposed when you cut the section out. The next step is to measure a perfect square or rectangle (depending on the shape of the rot) around the rotted section using the floor joist marks as two sides. Connect those parallel lines to make a box on the ceiling. Make sure that the box is at least 4 inches beyond the edge of the rot on all sides.
Cut Out and Replace the Drywall
Run your utility knife along the lines of the box several times until you break through the drywall and can remove the section. You may have to remove some screws, so have a power drill handy. Cut a piece of drywall to the exact size as the removed section and fasten it to the ceiling with drywall screws. The most important aspect of this is to have half of a floor joist on either side to attach it to, otherwise it will be partially unsupported at the end(s).
Ceiling Drywall Finish
The most time consuming part of the repair is the finish. Using all purpose drywall compound, fill in the 4 seams with mud and run tape over the sides. Press the tape into the mud with the drywall knife, remove the excess mud and let it dry. Return to it and apply a second coat of mud, wider than the first. Again, smooth it out, remove the excess and allow to dry. The third coat is the final coat. Try to make it as flat as the rest of the ceiling. After this step you can apply texture, primer and paint as necessary.
If you have larger sheets of drywall to hang on the ceiling, cut 2x4s to a length that measures from the floor to the ceiling joists minus the thickness of the drywall. These can be used to support the drywall as you fasten the screws. You can also use a tool called a drywall jack for this. The hardest part about repairing ceiling drywall is keeping your arms in an upright position for an extended period of time. Help yourself by finding ways to make it more comfortable.