How to Put in an Arched Doorway

Locate the position of the studs in the wall where you plan to install the doorway, using a stud finder. Drive a finishing nail into the wall around the studs, finding the exact edges of the studs. Draw vertical lines along the edges of two studs using a carpenter’s square, creating the edges of the doorway opening.

Measure the gap between the two vertical lines you created on the wall. Draw a line as long as the width you measured, using a large piece of cardboard. Draw a curved line to connect the ends of the line, using a carpenter’s square.

Cut out the arch design you made on the cardboard, and then trace around the design on another piece of cardboard. Cut out the matching arch design and tape them to the wall at the height were you want the doorway’s arch to sit. Position the edges of the templates so they touch the vertical lines you drew.

Trace around the arch templates you attached to the wall, and then remove the templates. Cut a 3-inch hole in the drywall inside the archway you traced, looking inside the wall for wiring or pipes that present an obstacle to the placement of the doorway.

Pry off the trim at the base of the wall, using a flat pry bar. Cut along the lines you traced, using a drywall saw, removing the drywall from the archway on both sides of the wall.

Trim blocks that are the same width as the space between the two sheets of drywall, in the arch portion of the cutout. Insert the blocks in the space between the drywall in the arch so the ends of the blocks are flush with the edge of the cutout. Drive wood screws through the drywall and into the wood blocks.

Cut strips of drywall to fit in the interior of the new arched doorway you created. Drive screws through the drywall and into the wood blocks or studs to hold the drywall in place. If the drywall does not bend to the contours of the arch, wet the backside of the drywall with a damp sponge until it bends without being damaged.

Press strips of drywall tape over the drywall seams. Apply a layer of drywall compound over the tape and the screws in the drywall, evening out the compound with a putty knife’s blade. Allow the compound to dry completely before applying a second coat.

Sand the dried compound with fine-grit sandpaper until it is as smooth as the drywall. Brush primer and paint on the archway to match the rest of the room.