How to Install an Interior Door Unit
- 1). Stand the door unit in the doorway. Position the unit so the edge of the casing is even with the edge of the jamb, the inward-facing part of the framed-in opening. Check that the door opens in the correct direction.
- 2). Push shims between the outside of the casing and the inside of the jamb. Wedge them in while holding your level along one side of the casing to make sure the unit is vertical. Continue shimming until it is level all around.
- 3). Access the inner edge of the casing by opening the door. Drive 2-1/2-inch wood screws into the casing and through the surrounding jamb with your screw gun. Set the screws in straight rows of two, spaced about every 18 inches. Drive the screws just below the surface of the casing.
- 4). Test the door to make sure it opens and closes properly. Cut off the overhanging shims. Door trim will cover the space between the casing and the jamb.
