A door frame is a building component used to hang a door. Frames used in residential buildings are typically made from wood, while those found in commercial structures are usually steel. No matter what material it's made from, the frame is made up of the same basic parts, each of which plays its own role in allowing the door to operate.
The two vertical supports on either side of a door frame are known as the jambs. On average, these jambs are either 6-foot 8-inches high or 7-feet high, though custom sizes are also available. The hinge jamb is used to hang the door, and the door is latched by fastening the lock strike to the strike jamb.
Horizontal beams at the top of a door frame are known as heads or headers. The standard frame head is 3 feet in length, with smaller and larger sizes also available depending on the application. Most heads are 2 inches high, though 4-inch-high heads are often used in masonry walls to allow the frame to align with normal brick coursing.
Soffit and Stops
Door frames have a protruding section that runs the entire perimeter of the jambs and head. This bump-out is known as the soffit, and each side of the soffit is called a stop. The stops are used to keep the door from swinging straight through the opening. When the door is closed, it rests tightly against one of the stops, which are usually 5/8 of an inch deep.
The two sections to either side of the soffit are called the rabbets, which are typically just under 2 inches wide. Modern frames are equipped with rabbets of unequal widths. This makes door installation virtually error-proof, as the door won't fit properly on the smaller rabbet. Some architects prefer the clean, even look of frames with equal rabbets, which must be custom made.
The face is the portion of the frame that is visible when the door is closed. There is a face on both sides of the door, and standard frames have 2-inch faces. In residential applications, the face of the frame is often covered by wood trim, though it is usually left exposed on a commercial opening.
The throat of a frame is equal to the thickness of the wall in which it will be installed, with 1/8 of an inch added for clearance. Frames that will be installed in drywall walls have components known as backbends, which keep the edges of the frame from damaging the wall during installation. Frames designed for masonry walls have shorter, simpler backbends, as damage is not a concern in masonry.