Door Jamb Installation Tips

Thickness and Height

• Order the proper doorjamb for the type of walls in the house. Walls that have plaster covering them are a different thickness than walls covered with drywall. For exterior doors, the thickness of the sheathing and siding can affect the thickness of the doorjamb, so measure there as well before you order a door. Another consideration when ordering a prehung door is the height of the flooring. If the room on either side of the door has thick carpeting, make allowances before installing the doorjamb rather than needing to make adjustments to accommodate the carpet after the door is in place. Typically, there should be about 1/2 inch of air space between the bottom of the door and the top of the carpet. For a smooth flooring material, such as tile or hardwood, the bottom of the door should barely touch the surface of the floor.

Door Hand

• When ordering a prehung door, know which way the door swings open. Carpenters refer to this as the door's hand. Determine which way the door swings to the inside of a room. In most cases it's the side of the door with the hinges. The hand you use to open the door, or pull it towards you, is the handing of the door. For example, if you are facing a door with hinges on the right that opens toward you, it is a left-handed door.

Positioning

• To help with positioning a doorjamb during installation, leave the packing braces in place. In other words, don't try to open the door until you have it in the opening. Use a carpenter's level to help level the doorjamb as well as to ensure it is plumb. Plumb the hinge side of the doorjamb. Push wood shims into spaces between the walls and the doorjamb at the height of the door hinges to hold the doorjamb in place until you can secure the doorjamb with finishing nails. Once the door is in position, remove the screws from the top hinge and replace them with screws that are long enough to go into the door's framing, which gives the door added support and helps to keep it from sagging.