Take the 2-minute tour ×
Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.

I want to cut the drywall on the ceiling accurately. The thing is that the drywall is thick and it is on the top. I have to stand on the ladder; one hand use utility knife and the other hand hold the drywall.

The expected shape is supposed to be rectangle. Cut drywall on the ground is easy, but it is on the garage ceiling(below unfinished attic). It is tough, any tips?

share|improve this question
    
Read your question, but I have some for you: - Are you taking down or putting up drywall? - What is on top? - How big, length and width is the rectangle? –  getterdun Nov 17 '13 at 2:42
    
Who looks at how straight a drywall cut is is in a garage ceiling? Good practice though, I suppose. –  Kaz Nov 17 '13 at 6:20

4 Answers 4

up vote 6 down vote accepted

Free Hand Utility Knife Technique

I personally have good luck with a utility knife freehanded. I use a straight edge to mark a straight line, often with a pencil instead of a utility knife. If you do use a utility knife with the straight edge, ensure you are keeping the knife vertical and don't apply too much pressure. Too often the blade will carve out the drywall under the straight edge, or pressure against it will push the straight edge off of it's mark.

The trick to straight freehanded lines is to use your body rather that your wrist. If you try to correct your line by shifting your wrist, the line will be all over the place. If instead you push the knife with your shoulder and elbow, keeping your wrist locked in one position, your lines will be much straighter.

Drywall Bit on a Rotary Tool

Probably the easiest method to cut drywall is with a rotary tool. Have someone hold a straight edge, or practice cutting straight lines freehanded since this tool will tend to push to the side. The advantages of these tools are speed, ease of use, and they can be adjusted to not go too deep so you don't run the risk of hitting utility lines behind the drywall.

enter image description here

This is not a recommendation for a specific vendor, sample images only.

share|improve this answer

Utility Knife

  1. Position a 2'- 4' level (or other straight edge) along the line you'd like to cut.
  2. With the straight edge in place, gently draw the utility knife along the line. You don't have to press too hard, just enough to cut through the paper on the face of the drywall.
  3. Draw the utility knife repeatedly through the groove you scored in the previous step.
  4. Increase the pressure slightly with each pass.
  5. Continue until the knife has cut through the drywall.

Once you score a line in the drywall, the utility knife will tend to follow the groove. So you'll only need to hold the straight edge in place for the first scoring pass.

Drywall Saw

You should be able to pick up a drywall saw at any hardware or home improvement store, for just a couple bucks. These saws have a sharp pointy tip, which makes plunging through the drywall easy. They also have coarse teeth, which make cutting the drywall easy.

enter image description here

They are often known as "jab saws", because you use them by jabbing them through the drywall to start your cut.

  1. Place the tip of the blade where you want to begin your cut.
  2. Smack the hilt of the saw hard, to force the tip through the drywall.
  3. Carefully make your cut using a back and forth sawing motion.

Power Tools

You could also use a rotary saw, or oscillating Multi-tool to quickly and easily cut drywall.

RotoZipOscillating Multi-Tool


WARNING:

Always be aware of what is behind the drywall, to avoid cutting into wiring, plumbing, or other hidden dangers.

share|improve this answer
1  
Drywall saws are great for cutting out holes in the middle of a gap, but ensure there aren't any utility lines (electric, water) behind the drywall first, and they won't help on cuts along a stud or joist. –  BMitch Nov 16 '13 at 16:34
    
The trick using rotating bits (a-la Roto-Zips) is to fasten the sheet lightly about 2 feet out from the hole you are making. Electrical boxes should be set so that they will be flush with the mounted drywall, which usually means they are 1/2 inch out from the structure. This lets you plunge the spinning cutter into the center of the box, push the bit to the edge of the box, then 'hop' the bit to the outside and trace around the box (or any hard surface the 'guide bit' can trace around. Go slow at the corners to not overshoot and have a helper suck dust away from your face with a shop-vac. –  HerrBag Nov 16 '13 at 17:13

Measure carefully and cut it on the ground? You seem to be involved in putting it up ("use one hand to hold the drywall") so that would appear to be a valid approach (as opposed to when you are trying to cut installed drywall). With a bit of care, results can be quite decent, and it involves less annoying messy work over your head.

If you are doing much ceiling installation, renting (or buying, depending how much - if bought used and sold after the work is done, it can cost you less than rental) a drywall lift/hoist simplifies ceiling installation, especially if you don't have a helper. With a helper, a T-support fabricated from lumber is often adequate and a lot cheaper.

share|improve this answer

How about a straight-edge which has mounting holes drilled through it? Screw the straight edge to the drywall (not too tightly) and then both your hands are free to do the cut, using the edge as a guide. Then unscrew the edge. The holes disappear when tape and mud is applied.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.