How To Cut Drywall Like a Pro

Cutting to length and width

When you’re hanging drywall, there’s more at stake than saving money or keeping on schedule. The next step, taping, is the toughest part of drywalling, and the keys to saving time and effort are making accurate cuts and knowing the tolerances. If a taper has to fix poor cuts, big gaps and ragged ends, you’ll eat up all the money you saved by hanging the drywall yourself. This photo series shows the basics of drywall cutting and the tools you’ll need for fast, accurate cuts. It concentrates on cutting to length, cutting door openings and ripping.

Score, snap and cut

Ninety percent of the cuts made on any drywall-hanging job consist of three basic steps: scoring the front paper, snapping and folding open the sheet, and cutting through the paper on the back. You’ll use variations on that theme for nearly every cut. Other cuts are made with two types of drywall saws: a small keyhole-type saw for short cuts (mostly electrical box openings) and a larger coarse-tooth saw for longer cuts like those around doors.

Working with drywall

Drywall is really just a simple sandwich of mined gypsum rock encased in a wrapper of recycled paper (hence one brand name, Sheetrock). Although neither component has much inherent strength, when combined they form a remarkably strong, highly fire-resistant wall sheathing. When you score the paper with a utility knife, the crumbly gypsum breaks cleanly, directly in line with the score.

When you’re scoring with a utility knife, use only enough pressure to barely cut the paper. Cutting deeply into the gypsum core will only result in dull knives and a strained wrist. When the blade stops cutting cleanly, you’ll notice the paper begin to tear behind the knife edge as you score. That’s when it’s time to change blades.

Here are a few hanging tips to help the job go smoother and with less waste:

• Hang all horizontal surfaces like ceilings and soffit bottoms before you start on the walls.
• Do intricate layouts with the sheets lying flat on the floor rather than standing on edge. It’ll be easier to use straightedges and chalk lines.
• You have to cut openings for existing doors and windows before you hang the drywall sheets (Photos 10 – 12). Protruding jambs and insulation prevent cutting the sheets in place. Make those cuts while the sheets are standing against the stack instead of mounted over the opening. It’s helpful to have another person support the sheet to prevent breakage while you cut, especially if the cutout calls for narrow, fragile drywall legs on either side of the opening.
• Save waste by cutting pieces to length before cutting to width.
• Use 12-ft. long sheets instead of 8-footers if you can handle the pieces and wrestle them into the room. The leftover pieces will be longer, so they’re more likely to be useful, and you’ll have fewer joints to tape.
• As much as possible, minimize the number of joints, especially hard-to-tape butt joints.

How to cut door and window openings

Attempting glove-tight joints will often result in cracks and broken corners when you’re forcing the sheets into place. You’re much better off cutting lengths 1/4 in. too short than trying to shoehorn in perfect fits.

When you’re cutting around windows and doors, remember that trim will usually cover at least 1 in. of the surrounding drywall, so you can afford wider tolerances. In fact, a 1/2-in. space between the opening frame and the drywall will often make applying wood trim easier.

But outside corners that get metal corner bead (Photo 10) are a different story. There, drywall joints should be overlapped and rasped as flush as possible. A 1/4-in. mistake on a corner can make fitting and nailing corner bead tricky and prone to cracks later. Also, avoid using the tapered edge of the drywall at any corner that receives corner bead. The recess of the taper won’t leave any gap between the outside bead and the flat drywall surface to fill with drywall mud.

Avoid drywall cracks

Always span openings with a single piece of drywall. Joints that fall in line with the edges of openings are vulnerable to stress cracks. It’s even best to avoid joints that fall over the middle of openings because it’s hard to apply wood trim over built-up tape joints.

Use your 4-ft. drywall square to mark the centers of framing members before you hang the sheets; you’ll miss fewer studs and joists when you’re screwing off the drywall.