How to Expand an Interior Doorway

Remove the trim from the doorway and the adjacent wall where you wish to expand the doorway opening. Slice the paint that bonds the trim to the walls using a utility knife and insert a putty knife under the trim, protecting the wall from damage.

Slide a pry bar over the putty knife, and then rotate the end you are holding toward you to loosen the trim on the wall. Move down the trim, using the putty knife and pry bar, until the trim comes completely off the wall.

Cut through the nails holding the door jambs to the wall studs, using a reciprocating saw with a metal-cutting blade. Pull the door jambs out of the doorway. Cut through the nails holding the door’s header board to the trimmed studs above the doorway and remove the header board.

Measure along the bottom of the wall how far you plan to expand the doorway, marking the measurement. Mark the same measurement at the top of the doorway, using a carpenter’s square to ensure the line is plumb. Connect the two horizontal lines with a vertical line, using the carpenter’s square to make a perfectly vertical line.

Cut a hole 2 inches in diameter with a drywall knife into the wall in the middle of the area you marked for the expansion of the door. Look inside the wall through the hole, shining a flashlight around to see if any pipes or wires sit inside the wall, providing an obstacle to the door’s expansion.

Cut along the lines you marked on the wall, using the drywall knife and pull down the drywall in the cutout using the pry bar. Cut through the wall studs along the same line you used to cut the drywall and remove the studs from the cutout.

Cut a new 2-by-4 board to the same width as the door cutout you made. Hold the board up against the studs above the cutout and drive nails through the board and into the studs to anchor it.

Measure the distance from the floor to the new header board and cut 2-by-4's for the door jambs. Slide the new boards on the ends of the cutout and drive nails through the boards and into the wall studs on either side of the doorway. Paint the new header and door jamb pieces to match the rest of the room.