- 1). Center the door jamb in the roughed-out hole. Use a level so the sides and the top of the jamb are level
- 2). Insert wooden shims every 12 inches between the top of the jamb and the roughed-out hole. Position them so there is a tight fit. Nail through the jamb and shims to secure the jamb. Double-check that the top of the jamb is still level.
- 3). Level the hinge side of the door jamb. Insert wooden shims near the lower hinge and partially hammer in a finishing nail. Do the same near the upper hinge.
- 4). Level and shim the opposite side of the door jamb in similar locations to the hinge side.
- 5). Close the door and check that it fits in the jamb properly. If not, remove the nails in the problem area and readjust the shims as needed. Once the door closes properly, hammer in the finish nails until the heads are flush with the jamb.
- 6). Cut off the ends of the wooden shims sticking out past the jamb. Score along them with a utility knife and then bend them to break them off. You can also saw through them with a handsaw.
- 7). Place the door casing in place and use finish nails to secure it to the wall.