Prehung door products make it possible for do-it-yourselfers to replace interior or exterior doors. The following directions for how to replace a door apply to an exterior door. The process will be similar when installing a prehung interior door except insulation and sealing will not be necessary. Here, the professionals at PJ Fitzpatrick walk you through the replacement process step by step.

How to Replace a Door Instructions

1. Pry away interior trim to expose jamb. Be careful if you plan on reusing trim.
2. Measure the rough opening to determine the prehung door size to purchase.
3. Be sure to note where the door knob is before buying a door.
4. Once you have the new door, take off the exterior trim.
5. Take the old door off of the hinges and remove the old hinges from the jamb.
6. Remove screws from the sill and jam. Cut around the jamb with a reciprocating saw as necessary to cut through old nails.
7. Pull out old door frame.
8. Have a partner help you lift new door into place for a dry fit.
9. Open door to confirm that it clears the floor. If it doesn’t, take the door out. Build up the sub sill with a fitted piece of treated wood.
10. Make sure that the sub sill is level. Adjust it with shims as necessary.
11. Apply caulk to the sub sill and bottom sill of new door.
12. Lift the new door into place.
13. Wedge shims into frame near top of door to keep it stable while you work.
14. Use more shims to get the door square and plumb in the frame opening. Aim for an 1/8″ clearance between jamb and rough opening.
15. Place shims behind hinges and use long screws on the hinges to attach them to frame.
16. Insert shims at lockset and deadbolt positions.
17. Open and close the door to confirm that it’s working properly.
18. Cut off ends of shims with utility knife.
19. Attach frame and sill with nails and screws.
20. Fill frame gaps with minimally expanding insulating foam. After it dries, trim off excess with putty knife.
21. Install door handle hardware.
22. Put interior trim back on.