Home fashions come and home fashions go, but ever since the Romans, arches have always been in style. Although drywall is flat as a frying pan, you can shape it into an arch—bend it to your will, if you will, using some tricks of the trade.
But first you must prepare an opening. Whether you're fixing an ugly arch or putting an arch in a doorway, the same techniques apply. If you're simply drywalling a wall that already has an arch, skip ahead to Step 6: Drywalling Over an Existing Arch.
Step 1: Making the Pattern
You have two choices in making a pattern: Either copy an existing arch, or make a new shape. In either case, make a half pattern, and then use it on both sides. That ensures that both sides are symmetrical.
Copying an Existing Arch
Clamp a large piece of cardboard, stapled to a wood stiffener, across the archway you'll duplicate. To hold the pattern level, measure up from the floor to find the starting point, and then trace the arch on the cardboard.
Drawing a New Pattern
Make every effort to minimize damage during demolition. Don't loosen, crack, or gouge any more wall than necessary. Work slowly. Cut around anything you remove so the wall surface breaks cleanly. You'll probably have some damage to repair, but less is definitely more.
If you don't have an arch to duplicate, draw the shape freehand or with homemade drawing tools, following these suggestions:
Draw long-radius curves with a homemade compass. Tie a pencil to a string, have a helper stand on the other end of the string, and draw an arc. (Although few arches are fully circular, the arcs of a circle are helpful drawing guides.)
Sketch lightly on cardboard until you find a curve you like.
Cut the rough pattern (use a jigsaw, if you have one), hold it in place, and eyeball the shape.