A header is a critical horizontal structural member that spans an opening in a wall, such as a window, door, or interior passageway. Its primary function is to act as a bridge, collecting the vertical loads from the structure above—including the roof, floors, and wall studs—and redistributing that weight to the vertical support members, known as jack studs, on either side of the opening. Typically constructed from dimensional lumber, steel, or engineered wood products like Laminated Veneer Lumber (LVL), headers ensure the structural integrity of the building envelope by preventing sagging, cracking, or failure of the wall where the continuous load path has been interrupted. While often concealed within the wall framing, headers are essential components in both load-bearing and non-load-bearing applications, with their depth and thickness determined by the span of the opening and the magnitude of the anticipated loads.