A plaster ceiling is made out of a mixture of lime/gypsum, sand, water and some form of fiber. Once the plaster dries, it becomes a hard and durable concrete-like substance, which makes it fairly difficult to cut a hole in a plaster ceiling. Holes are often required when the ceiling is damaged due to a roof leak, an accident, or furniture shifting.
Cutting a hole in a plaster ceiling is typically an easy job; however, if your your plaster ceiling is part of an old construction, special care must be taken. The same goes for situations in which the damage to the plaster ceiling is such that the integrity of the structure has been compromised,. In such cases, follow these steps to cut a hole on a plaster ceiling
Step 1 - Safety Precautions
Sagging and cracks are signs that your plaster ceiling needs to be repaired. Before you begin task of cutting a hole in the plaster ceiling, it is important that you wear thick leather gloves so that the metal does not damage your skin.
Turn-off the main power switch of the house before doing any work. Safety glasses and a dust mask are also advisable so that you don’t inhale plaster dust, which can damage both your lungs and skin. A hard plumbing hat should also be worn to avoid injury in case any lose scraps of plaster fall down.
Step 2 - Drilling
Using the largest drill bit available, drill holes through the damaged area. The more powerful the drill, the easier the task will be, as it will require less manual effort on your part. Space the holes an inch from one another.
Once the holes have been made, drill straight lines to frame the selected area. Don’t forget to check for plumbing pipes or wires before you drill. After drilling, use a hole saw in the first hole with another saw in the second and the following holes.
Step 3 - Cutting
After you have drilled the first hole, put a piece of plywood against the ceiling as a guide. Temporarily attach the plywood to the joists with screws. As you prepare to make the cut, ensure that the saw blade is as thick as the combined plaster and lath. That way you can cut the plaster without damaging the joists.
Using a circular saw with a masonry carbide blade for cutting. Cut through both the plywood and the plaster simultaneously. Doing so prevents damaging the ceiling and will stop plaster from falling in pieces while you cut.