Which description best defines a header?

• A. A member that spans a door opening and supports the structure above.
• B. A trim piece installed around doors.
• C. A floor joist under a doorway.
• D. A decorative molding.

Answer: (A)

In wood framing, a header is the horizontal structural member that spans an opening, such as a door, and carries the weight of the structure above down to the sides. It acts like a beam, transferring load from the wall above to the studs on either side, and is supported at its ends by jack studs (trimmers) with usually a king stud nearby for stability. Headers are often built-up from multiple boards or use engineered lumber to meet the required span and load.

This description matches the purpose of a header: spanning the opening and supporting the structure above. It’s not just trim around a door, not a floor joist under a doorway, and not decorative molding—those elements serve cosmetic or separate structural roles.