Understanding Door Frame Horns

A door frame is an essential part of any opening in a wall, providing the structure to which the door is attached. The frame needs to be securely fixed into the surrounding wall. Various components of the door frame serve specific functions.

The question asks about the horizontal projections located at the top (head) and bottom (sill) of a door frame. These projections are designed to be embedded into the side walls. This embedding helps in securely fixing the door frame into the masonry or concrete wall, preventing movement and ensuring stability.

Let's look at the terms provided:

• Horns: These are indeed the horizontal projections at the head and sill of the door frame. They extend into the side walls and are a primary means of anchoring the frame securely.
• Holdfasts: Holdfasts are metal straps or anchors, usually made of mild steel, that are fixed to the back of the door frame members (like the jambs). These straps are then bent and embedded into the wall masonry or concrete during construction to provide additional fixing points. They are distinct from the frame's wooden projections.
• Jambs: Jambs are the vertical members on either side of a door frame to which the door hinges are fixed and against which the door closes. They are part of the main frame structure, not projections embedded into the side walls.
• Rebates: A rebate is a groove cut into a piece of timber (like a door frame) along one edge. In a door frame, the rebate is where the door panel sits when closed, creating a flush or overlapping joint and helping to seal the opening. It's not a projection used for fixing.

Based on the descriptions, the horizontal projections at the head and sill of a door frame that are embedded into the side walls for fixing are known as horns.