How to Replace Pre-Hung Doors

Slide a utility knife around the seam between the trim surrounding the door and the wall. Cut the seam around the trim on all sides of the door, including both sides of the wall. Failure to cut the trim caulk can lead to damaging the wall finish surrounding the door.

Push the end of a pry bar under the pre-hung door side of the trim. Hit the end of the pry bar with a hammer if it will not slide between the trim and door frame. Push the bar toward the door to release the trim from the wall. Move along the trim – repeating the process – until all trim has been removed from the door.

Remove the hinge pins from the door hinges by prying up on the head of the pin with a flat-head screwdriver. Start with the bottom hinge and work your way to the top. Pull the door off the hinges and set it aside.

Install a bi-metal blade in a reciprocating saw. Slide the blade in the gap between the door frame and the framing of the opening. Cut through the fasteners holding the frame in place with the reciprocating saw. Pull the frame from the opening.

Slide the new pre-hung door into the opening. Center it in the wall. Place wood shims between the frame and the wall opening to hold the door in position. Place a level against the vertical hinge side leg of the pre-hung door. Run a 3-inch wood screw through the door frame, wood shims and wall framing with drill/driver containing a Phillips tip adapter. Move along the hinge side of the frame until it sits securely in place. Repeat the procedure along the top and latch side of the door frame.

Trim all wood shims even with the wall by sliding the utility knife along their faces and snapping them off.

Measure the length from the floor to the top corner of the pre-hung door frame. Cut four lengths of wood trim at the measured length with a power miter box. Hold one piece of trim in place. Secure the trim to the door frame by running one finish nail every 12 inches with the hammer. Install all vertical trim. Measure the distance between the top of two pieces of installed vertical trim. Cut the trim to length and install across the top of the pre-hung door. Install the top piece of trim on the other side of the door.