Build an Archway
In this article, you will find:
Drywall and finishing
Step 6: Drywalling over an Existing Arch
You may need to cut an arch shape in drywall while drywalling an existing wall. If you have a rotary tool like a RotoZip, you can cut the drywall in place. Otherwise, have a helper hold drywall against the arch, mark the arch, and remove it while you cut it.
Cutting with a Saw
To mark the drywall and cut with a saw, follow these steps:
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Place the sheet of drywall in its final location. Try to span the entire arch with one sheet.
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Have a helper hold the sheet against the wall, and mark the curve from behind. Then remove the sheet, support it carefully, and cut with a jigsaw or a hand drywall saw. Return the sheet to position and fasten.
Cutting with a Rotary Tool
The second way to cut an arch is slicker and faster—but only if you have a rotary cutting tool like a RotoZip. To use a rotary tool, follow these steps:
Dave's Don'ts
The RotoZip is handy, but the dust will fly right through most vacuums (trust me on this one). Without a vacuum, much of the dust will fall to the floor for easy cleanup. Don't forget to wear ear and eye protection when operating a rotary tool.
Mark a spot just inside the arch on the new drywall.
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Screw the sheet in place.
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Install a “guide point” bit. (These follow the shape of whatever is behind the new drywall.)
Adjust the cutting depth. Set the rotary tool so it will poke 1⁄4" through the new drywall.
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Place a corner of the rotary tool at the mark from step 1. Start the tool and rotate it until the base lies flat on the drywall.
Move sideways until you feel the arch, and then follow the arch to make the cut.
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After the cut, leave the sheet fastened to the wall.
Nail the flexible corner bead first to the underside of the arch, and then to the flat wall. If you use rigid corner bead on the flat stretch below the arch, make a smooth transition between the corner beads.
Step 7: Finishing Up
At this point, all you have to do is to finish the drywall. This process is explained thoroughly in Drywall an Existing Wall.
Easy-to-use, self-stick fiberglass tape bridges the joints. For small gaps, apply tape under patching material. Patch larger gaps first with quick-setting compound. After it dries, apply the tape.
I use two different patching compounds for most drywall work. Powdered, setting-type joint compound fills deep areas and sets quickly. Keep it below the final surface. Use normal drywall joint compound to smooth the wall.
Fill the underside of the arch with quick-setting compound. Half an hour later, you can trowel on drywall compound. Sanding and more drywall compound will blend this arch with the wall.
After a bit of a mess and a lot of careful marking and cutting, the reward is an arch that matches the prototype. It's an arch that looks as old as Rome.