1. Removing the Old Door
Break apart the caulking on the trim of the door.
Remove any trim surrounding the door frame.
Remove any nails or screws attaching the door frame to the studs of the wall.
Once the nails and screws have been removed, close the door and tip it back toward the direction in which you removed the trim.
2. Prepping the Site and the Door
Start by checking your rough opening.
Prep the door for installation.
3. Installing the New Door Using Brackets
Use a bracket system for efficient hanging of doors.
Using a 4- or 6 foot (1.2 - 1.8 m) level, draw a vertical plumb line on the drywall 1/2 inch (1.27 cm) in from the rough opening.
Screw three brackets to back of door frame, beside the hinges.
Screw the other three brackets on the latch side of the door.
Place 1/2" (1.27 cm) blocks on the bottom of the floor for carpet, and 1/4" (0.635 cm) blocks for vinyl or laminate.
Starting at the top hinge, match up one of the lines on the bracket with the level line drawn at the beginning.
Screw the door to the wall using the drywall screws provided.
Next, check the clearance between the frame and the door on the top and knob side.
Starting at the top again and working down, continue screwing the screws into the your brackets on the latch side.
Install any trim over top of the brackets.
Place three shims at the location of each hinge on the inner part of the door.
Drill a pilot hole through the doorstop and the shims, and then hammer in a nail into the upper shim in order to hold the door into place.
Check that the door is completely straight and plump with a 6 foot (182 cm) level.
Drill pilot holes through the doorstop and shims at the middle and lower shims.
Line up three more shims on the latch side of the wall, directly across from the shims on the hinge side.
Drill pilot holes through the doorstop and shims at the upper, middle, and lower shims on the latch side.
Put shims into two locations at the top of the door frame.
Pre-drill eight pilot holes at each of the shim locations on the narrow side of the jamb.
Sink the heads of the nails completely into the jamb using a nail set.
Replace the hinge screws with 2-1/2" (6.35 cm) screws to add more stability and balance.
Break off any portion of the shims that are protruding from the door jamb.
Install any trim over the door frame.