What is Drywall?
Drywall is also known as plasterboard, wallboard or Sheetrock. It is a dried, pressed gypsum cement that comes in thicknesses from 1/4” to 3/4” and come in widths up to 54” to use on ceilings and walls. Longer sheets can be troublesome as they are heavier but there are less joints which will make finishing easier. When hanging drywall you’ll need to start with the ceiling first and then the walls. There are really two basic ways of cutting drywall, these are either sawing or scoring. Which method works best depends on what you are trying to do with it, for example, scoring is better if you are trying to cut sheets at a length while sawing is better for holes and openings.
What tools do you need?
Drywall keyhole saw
Circle Cutter (if needed)
Start with your drywall standing or laying flat and evenly supported. Measure the drywall to where you want the line. Mark the line across the drywall vertically in several places along the width. Using the straight edge mark across and intersect the vertical marks across the board using a straight line.
Take the utility knife and score along the marked line through the paper and into the core. You do not need to cut the board through, just past the paper and into the gypsum. Support the sheet on the back and apply pressure to the face on one side of the score. The board should snap cleanly to the paper on the other side. Using the utility knife again cut the back paper on the sheet at the fold. Using a drywall rasp smooth the cut edges out.
This method is best used for smaller pieces of drywall that are smaller than 3ft across any larger makes it hard to keep the pressure even on all parts of the score to break it, risking the cut not going through the scoreline in places.
Method 2-Sawing Doors
As you can see from the list above there are two types of drywall saws. A keyhole saw is used for making smaller cuts like those needed for electrical boxes while the large drywall saw is better for windows or doors. Mark the location for the cuts using the straight edge and the measuring tape. Remember to measure twice before cutting. This may be easier to do before installation depending on where your cuts are.
When creating a door measure from the corner of the room to the edge of what will be the door jamb and then mark the same measurement onto the drywall if it has not already been hung. Mark the wasted piece with a large X so you know which is which. Measure the vertical height for the door and mark that on the sheet too. Start with the shorter cut using the drywall saw. Score along the long edge using the utility knife and snap off the waste piece.
Method 3 – Sawing Electrical Boxes
When cutting an electrical box you’ll be working with a much tighter space. The most common method of doing this is to mark the location and then use the box itself as a cutting guide. Hold the box onto the drywall and mark around the outside with a pencil. Using a keyhole saw cut around the opening. Push the sharp point of the keyhole saw into the sheet then hold the saw at a slight angle so that the back is slightly larger than the front for a snug fit. Use a utility knife to even up the edges, leaving no more than a 1/8” gap around the box.
Method 4 – Power Tools
A rotary or multi-tool sounds like a quick way around not having a keyhole saw, the problem is that you’ll need the right bit or you can make a huge mess. A downcutting bit is important if you’re working with drywall that’s already been hung and only needs a small cut.
You can find drywall bits for as little as $3. Start by marking the area the same as you did with method 3, using a drill out one corner of the marked area enough to fit the multi-tool bit in. Carefully use the multi-tool to trace around the marked area.
This is by far the hardest method as the weight and speed of the power tool makes mistakes much more likely, especially if you can’t guarantee to have a steady hand.
Method 5 – Compass/Circle Cutter
Cutting circles in drywall are not as difficult as it might sound, the method is much the same of that as sawing an electrical box. You can use a keyhole saw to cut small circles if you feel confident with it.
A circle cutter is much more convenient though, it has two sharp wheels that pivot around the center tip to evenly cut the plug out which can then be removed. Mark the circle using a compass so that you have a small indent where the exact center is. Slide the wheels to the diameter of the required circle and place the center tip into the indent from the compass. Firmly turn the wheel around so that the wheels score out the circle. Pop the circle through and remove.
Drywall can be heavy, you’ll want a helper or a drywall lift for larger pieces so they don’t break. Use a pencil or a scoring tool rather than pen as the ink from pens can bleed through when you start painting, the same goes for the old trick of using lipstick to make electrical boxes. Keep a spare blade for your utility knife as it will quickly dull against the gypsum. Throw away scraps or place them in a designated area so that you don’t get them confused, also make sure they are properly marked as scrap so that you don’t use them on accident.