A grademark identifies the species, grade, grading agency, and mill number. This information allows the product to be traced to the mill of origin, as well as establishing the structural properties of the piece of lumber.

Most 2x4 dimension lumber is visually graded and marked with an ink stamp at the mill. The markings on this bunk of lumber provide information to assure the product has the strength for the application.

Bay window headers support a small roof. An LVL header in the foreground supports the floor joists above and the exterior wall and roof.

Headers are revealed in exterior and interior wall framing. Where interior walls are non-load bearing, headers are not required.

A long-span header is used to carry load across a complex window design.