A door jamb is the vertical portion of a door frame that supports the door, hinges, and proper alignment within an opening.

A door jamb is the vertical component of a door frame that forms the sides of the door opening and supports the door’s hinges and latch hardware. Along with the head jamb at the top, it creates the structural framework that allows a door to open, close, and seal properly within a wall opening.

In construction, door jambs are typically installed during the framing or finish phase, depending on whether the door is site-built or prehung. They are commonly made from wood, MDF, steel, or aluminum, with material selection based on application, fire rating, durability, and aesthetic requirements. Precise alignment and plumb installation are critical to ensure smooth door operation.

Door jambs also play a role in sound control, fire resistance, and weather sealing when paired with appropriate stops, gaskets, and thresholds. In both residential and commercial projects, properly sized and installed door jambs help maintain clearances, support hardware loads, and meet applicable building code requirements.

The word “jamb” comes from an old French term meaning “leg,” a nod to how door jambs act as the “legs” supporting the doorway.

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