Jambs

A jamb is the vertical side of an opening in a wall, such as a doorway or window. Jambs are part of the frame that supports the door or sash and transfers loads from the door to the surrounding wall. They help define the opening and provide mounting surfaces for hinges, lock hardware, and trim.

There are different types of jambs based on the opening. A door jamb is installed on either side of a door opening; the hinge jamb houses the hinges, while the strike or lock jamb receives the latch or deadbolt. A window jamb surrounds a window opening and provides attachment points for the window frame and casing. In masonry walls, jambs may be formed by the surrounding brick, stone, or concrete and then finished with trim or casing.

Materials and construction vary. Wood is common for interior doors and windows, with jambs milled to accommodate hinges, strike plates, and casings. Metal frames, including steel or aluminum, offer added strength and fire resistance. In masonry or plaster walls, jambs can be built into the opening and later faced with trim. Vinyl or fiberglass jambs are used in some modern installations for durability and low maintenance.

Installation considerations include ensuring the jambs are plumb, level, and square within the rough opening. They are fastened to wall studs or the surrounding masonry, with shims as needed for alignment. Weatherstripping, insulation, and finishing casings or trim are applied to seal gaps and provide a clean, finished appearance.

Historically and in contemporary practice, jambs serve both structural support and aesthetic framing, with variations reflecting regional building traditions and architectural styles.