Coming in large 4-foot by 8-foot sheets, drywall is typically installed in full sheets on walls and ceilings. Even then, there always comes a moment when those sheets need to be cut, either width-wise or length-wise.
Cutting large sheets of drywall can be a hassle. A sheet of drywall can weigh over 50 pounds. Not only that, drywall is wobbly and hard to manage. But there are a few tricks to cutting sheets of drywall easily, even without setting the sheets flat on the floor.
Cutting drywall with a utility knife poses the risk of cutting fingers or legs when slicing along the straightedge part of the square. Do not use your knee to hold the square in place as you cut. Keep your free hand and fingers well away from the blade.
Equipment / Tools
- Utility knife
- Utility knife blades
- Drywall square
- Tape measure
- Drywall sheets
How to Cut Large Sheets of Drywall on the Floor
Clear the Floor
Make sure that the floor is flat, level, and clean. Uneven flooring may cause the drywall to crack or buckle. Debris will embed in the drywall. Clean the floor with a broom or shop vacuum.
Lay Out Drywall
Make sure you have plenty of room to work. You'll need the size of the drywall (4 feet by 8 feet) plus another 3 feet around the perimeter to work.
Mark Drywall Sheets
Mark the cut point on the drywall sheet with the pencil. For a quick cut, you only need to make one mark, then rely on the square pressed alongside the drywall's factory edge to indicate the line all the way across.
But for precision work, it's a good idea to make two marks, one on each side. For example, if you are cutting 2 feet off of the end of an 8-foot sheet of drywall, mark down 2 feet on the left side and then 2 feet on the right side.
Lay Out Straightedge
Connect the two marks with the straightedge. Hold your fingers on the "T" area of the square, behind the direction of the cut.
Cut Drywall Paper
Lightly run the utility knife along the straightedge to cut the drywall paper. With the square still in place, run the knife a second time along the same line.
Flip Drywall Sheet
Carefully turn the sheet of drywall over.
Grab the edge of the drywall with your fingers. Tilt the drywall up until the drywall breaks (with the paper still in place). If the drywall doesn't break on its own, give it a gentle shake to encourage it to break.
Tilt Pieces Inward and Make Cut
Tilt one side of the drywall up to about 90 degrees. Hold it in place. With the other hand, slice the paper holding the two sections together. The two pieces will now be free.
Be careful toward the end of the cut as the paper will want to tear away.
How to Cut Large Sheets of Drywall on Edge
If you don't have enough room to lay out the drywall sheet, this method allows you to both score the sheet and cut it while the sheet is on its edge.
To cut the drywall sheet lengthwise, first lay it on the floor on either of its lengthwise edges. Rest it against a wall.
With the 48-inch drywall square, square the "T" end with the left side of the drywall. Make sure that it is firmly squared. With your utility knife, score a line as far as you can.
Next, square up on the right side. Complete the score.
Snap Drywall From Behind
Place the sheet of drywall on one of its short ends. Reverse the sheet so that you are facing the back of the drywall (the unscored side).
Roughly locate the scored area. With your knee, hit the drywall. Be firm and decisive as you contact the drywall. The drywall should break perfectly along the score line.
Complete Cut and Separate
With the drywall still on edge, remain on the back of the drywall. Fold the two pieces inward until they form a broad V-shape. Carefully run the utility knife down the drywall paper at the V-shape to cut it.
When to Call a Professional
Cutting drywall is a task that rarely requires professional assistance. But as part of a larger drywall installation project, you may want to have professionals cut, hang, mud, sand, and finish the drywall.