How to Make an Arch in an Existing Doorway

Use the crowbar and hammer to pry up the floorboards and drywall paneling surrounding your doorway. Remove the attached door by using your screwdriver or drill and place it to the side. Remove the door hinges as well.

Cut the seams of the doorway paneling with your utility knife to separate the paneling from the drywall. Pull out any small nails using pliers or your hammer. Complete this process slowly so as to not damage the drywall paneling; you will be able to reuse this undamaged paneling later in the process.

Measure the width of the doorway and thickness of the door jamb. Purchase a ready-made archway from a home wares store that corresponds with your measurements. Most archway sets come equipped with side columns as well. You may need to cut the top wall of your existing doorway with your drywall saw to make room for the arch you purchase. The amount of drywall cuts needed will depend on your measurements prior to purchasing the arch.

Cut your two-by-four lumber into three pairs of small wooden blocks, each at a different length. Fit the first pair horizontally to the top corner of your doorway. Fit the second pair vertically to the top corner of the doorway, forming an "L" with the first pair. Fit the third set of blocks diagonally within the doorway to meet the ends of the other two block pairs. This will serve as a support framework for your project.

Use your measurements and circular saw to cut four pieces of drywall that you have purchased. Each piece will be triangular to fit the blocks you have placed within your doorway. Use your drill and 1 1/14-inch screws to attach the drywall pieces to your wood block pairs. Spackle the screws with putty by using your putty knife.

Reattach the drywall paneling by screwing it back into place via the original screw holes. Follow your archway manufacturer's instructions to drill into your purchased support columns and place them on either side of the doorway. Line up the tops of the columns to the outside edges of your arch. Hammer the columns into place using your hammer and penny nails.

Spackle over all nail and screw holes once finished. Use drywall putty to fill in any gaps in the drywall or to correct any mistakes in the wall. Use sandpaper to smooth out the drywall and wood pieces.