How to Build an Archway in a Wall

Measure the width of the doorway and transfer the measurement to a piece of cardboard. Draw an arch design, connecting to the two ends of the line you originally drew on the cardboard, using a carpenter’s compass.

Cut out the arch design from the piece of cardboard. Lay the arch cutout on a second piece of cardboard and trace around. Cut out the second, identical arch design from the cardboard.

Cut through the paint at the edges of the door trim, and then insert a metal putty knife’s blade under the trim. Push a pry bar between the trim and the putty knife’s blade, and then push the end of the pry bar toward the door opening to pull the trim’s nails out of the wall.

Tape the cardboard arches to the wall above the doorway, lining up the bottom edges of the arches with the top edge of the doorway. Trace around the cardboard arches and then remove them from the wall.

Cut through the drywall, following the lines you traced, using a drywall knife. Pull the drywall inside the arch cutout off the wall and cut through the wall studs at the edges of the cutout, using a reciprocating saw.

Cut wood blocks to fit in the space between the drywall, at the top of the arch. Spread construction adhesive on the sides of the blocks and slide them into the gap at the top of the archway. Drive wood screws through the drywall and into the wood blocks, further securing them in place.

Measure the depth of the archway and cut strips of drywall of the same width. Wet the backs of the drywall strips with a damp sponge, stopping once the drywall can bend without breaking. Position the drywall strips on the inside of the archway, and drive wood screws through the drywall and into the wood blocks.

Stick drywall tape over the seams at the edges of the drywall strips you installed. Spread two to three coats of drywall compound over the tape, allowing the compound to dry in between coats. Sand the compound after the final coat has dried, using fine-grit sandpaper, until the patches match the surrounding drywall’s texture. Paint the interior of the archway to match the surrounding walls.