Rip Drywall to Width With a Tape Measure and a Knife — No Square

The Problem

Ripping drywall lengthwise means a long straight score, and a four-foot T-square only reaches four feet — for an eight- or twelve-foot rip you're snapping a chalk line or walking the square down the sheet in stages. Both work; neither is fast when you're cutting strips all day.

The Technique

Drywallers gauge the rip with the tape itself:

1. Pull the tape to your rip width and pinch the housing so it can't move.
2. In the same hand as the tape's hook end — or riding against it — hold the utility knife so the blade sits at the hook, on your measurement.
3. Hook the tape over the factory edge of the sheet, blade touching the face.
4. Walk down the sheet, sliding the whole assembly: the hook rides the edge as a fence, the tape holds the width, and the blade scores a parallel line the full length in one pass.
5. Snap the sheet along the score and cut the back paper as usual.

The tape-and-edge combination works as a marking gauge — the same principle woodworkers use to scribe with a tape and pencil, with the blade doing the marking and cutting in one motion.