What is the primary function of a door jamb?

The primary function of a door jamb is to frame the opening for a door and support the door. A door jamb is the vertical part of the frame that secures the door in place, allowing it to swing open and closed properly. This support is critical, as it ensures that the door is aligned correctly and operates smoothly, preventing sagging or misalignment over time.

While enhancing the appearance of a door can be an additional benefit of door trim or decorative elements, the main purpose of the door jamb itself relates directly to structural integrity and functionality. A door handle, on the other hand, is a separate component that allows for operation of the door, and thermal insulation is typically not a function associated with the jamb, as that role is more relevant to the entire door and framing assembly.