There are a number of reasons you might need to cut a hole in a plaster wall. Maybe, you need to gain access to pipes or eradicate the home of unwanted insects. Whatever the reason, cutting a hole in a plaster wall can be quite difficult. Plaster walls are much harder and denser than those constructed from drywall. If you hope to cut a hole in the wall without destroying the finish on the entire wall, you need to follow a specific procedure.
WARNING: It is best to begin this project only if you know what's behind the surface of the wall. You need to be careful not to cut into any plumbing or electrical installations, which could lead to fatal injuries.
Step 1 - Mark the Area With a Pencil
Outline with a pencil the area you’d like to remove. You may want to move out a bit from the actual area to ensure that the hole is large enough.
Step 2 - Punch in the Center of the Area
Using your screwdriver and hammer, punch a hole in the center of the area. Place the head of the screwdriver in the center and then tap it with the hammer until the wall gives. Continue in this manner until you have created a hole large enough for your reciprocating saw blade to enter.
When you first attempt to punch in the center of the area, use a great deal of force. Remember, this wall is not made of paperboard. Plaster is much harder and heavier, and is going to require more force and effort.
Step 3 - Set up the Saw
Once the opening in the center of the area is large enough for your saw blade to enter, it’s time to work with a little more power. A reciprocating saw is not very expensive but for a one-time job you may want to rent one from your local home improvement store. For a small fee you can have a professional tool without having to pay the full purchase price. The reciprocating saw is going to cut through the wall pretty easily.
Attach a 6-inch wrecking or demolition blade to the saw. These blades are strong and thick, and designed to cut through nail embedded wood, metal, plastic, and other materials. They won't bend or torque as easily as all-purpose blades. Using a longer blade risks damage to the back of the wall on the opposite side of the framing.
Step 4 - Follow the Pencil Line With the Saw
Start at the hole you punched and cut from the center out to the pencil line. Set the blade in the hole and pull the trigger. Let the weight of the tool do the work for you. Keep a steady hand, and follow the line you outlined as best you can.
The saw is going to cut through both the lathe and the plaster. This will enable you to get all the way into the wall. When using a reciprocating saw, go slow and steady to make a clean cut instead of a jagged edge. This will make the hole easier to repair when the time comes.
That’s it. With a few tools and a little bit of patience, your plaster wall can be opened easily.