Drywall can be easily cut using a straight edge and a utility knife. It consists of a layer of ground gypsum sandwiched between two thick sheets of paper, with the paper reinforcing the gypsum and providing a paint-ready surface when finished.
How to Cut Drywall
To cut drywall, simply slice the paper on both sides of the gypsum, causing the gypsum to break along this line. Follow the steps below for cutting a full sheet of drywall:
- Position your foot at the bottom of the T-square to keep it in place and prevent it from swaying at the bottom, ensuring a straight cut.
- Using a utility knife, score the paper by cutting along the right side of the T-square, starting from the top of the drywall sheet and moving downward. After cutting more than halfway down, flip the knife and cut from the bottom to complete the cut.
- Gently lift the board and bend it to break the gypsum along the scored line. The paper on the back of the board will remain intact, holding the board together.
- Cut the paper on the back of the drywall sheet to completely separate the two pieces. Smooth the cut edge by using a rasp along the freshly cut board to remove any rough edges.
Making Angle Cuts in Drywall
The instructions above don’t cover the techniques needed for making angled cuts or ripping a sheet of drywall along its length. Carpenters use various methods to calculate angles and distances for cutting drywall.
The fundamentals described above remain applicable. Cutting a sheet of drywall involves slicing the paper on both sides of the board and bending the board to fracture the gypsum inside. Many professionals use chalk lines to mark the pattern on the drywall sheet before cutting.
Cutting Around Pipes and Electrical Boxes
When installing drywall, rough electrical and plumbing work is often completed, requiring cuts in the drywall to accommodate fixtures. For such situations, consider these tools and techniques:
- Manual circle cutting tools are available for cutting circles larger than three inches in diameter.
- An invaluable tool is the keyhole saw, featuring a long, slender blade with coarse, saw-like teeth attached to a handle. It easily cuts through drywall and can create holes in the middle of a drywall sheet.
- Many electricians rely on a keyhole saw to cut small holes in already installed drywall. It’s a quick and efficient way to make small holes or angles in the middle of a sheet.
Most professionals heavily depend on light-duty electric routers equipped with bits designed specifically for drywall. These bits have an edge that guides them around electrical boxes or window frames, while the rest of the bit cuts through the drywall. This allows you to hang a sheet of drywall over electrical boxes and cut them out once the sheet is secured with a few screws.
A well-known brand for this purpose is RotoZip®, which is synonymous with drywall routers. This significantly enhances efficiency, as you spend less time measuring precise cuts and more time installing drywall. It’s important to note that using a router for drywall cutting is not recommended for beginners, as it requires specific training from a skilled professional.
Always Prioritize Safety when Using a Utility Knife
Working with a utility knife involves inherent dangers. One of the most common injuries when cutting drywall occurs when the knife slips along the edge of the T-square. The knife can easily slide from the drywall and run along the face of the T-square. If your hand is in the knife’s path, you may find yourself in the emergency room, likely needing stitches for your thumb or index finger.
Always pull the knife away from your body, never towards it. Be mindful of your hand’s placement as you hold the T-square and avoid having it in the cutting path. Recognize the potential risks associated with using a utility knife and practice safe working habits. If you have any questions or concerns, seek guidance from a trained professional.
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