What Is The Jamb And How Do I Know What Size To Order?
The jamb size refers to the depth of your doorframe. The jamb size should match the thickness of the walls. For example, if your home has 2x4 framing, you will order a 4 9/16 threshold to allow for the drywall and exterior siding.
The frame or jamb holds the door in place. By ordering a door unit that is prehung, the door and the doorframe or jamb have been assembled with the hinges.
When the door unit is installed, the jamb is attached to the rough opening. The sides of the frame or jamb are referred to as the Vertical Frame or “side jambs,” the top horizontal piece is the “head jamb” and the bottom horizontal piece is the “threshold.”