Jamb

Door jamb, a part of the frame, plays an important role in the smooth operation of any door. Used to hang your door, it takes the weight of the door and allows for the door to be plumb/level so the door swings free as it opens and closes to prevent wear on both your door and the frame.

There are three main types of Jamb:

Flat Jamb
As the name implies, a flat jamb is a flat piece of wood, usually ~ ¾” thick
at the width of the wall in which the door and frame will be installed. As a
flat jamb has no built in stop, either a flat stop, or T-stop needs to be installed separately to prevent the door from swinging past the mid point of the door frame. The stop is often ~ 3/8” – 5/8” thick.

Single Rabbeted
Unlike the flat jamb, a rabbeted jamb has the stop built in. Often ~ 1-1/4”
thick by the thickness of the wall, this type of jamb ensures that the stop is
plumb/level with the jamb and eliminates the need to install an additional stop after the jamb is installed.

Double Rabbeted
This type of jamb provides the appearance of a flat jamb, with the
convenience of the stop being built-in like the single rabbeted jamb.