Header in Construction: What It Is and Why It Matters

A header is a horizontal structural member installed above a door opening, window opening, or any opening cut through a load-bearing wall. Its function is to transfer the load that was previously carried by the section of wall that was removed, redistributing that weight to the framing on either side of the opening and ultimately to the foundation.

In remodeling, headers are required any time an opening is created in or enlarged within a load-bearing wall. The size of the header, in terms of its depth and material, is determined by the span of the opening and the load it must carry. An undersized header will deflect over time, causing door frames to rack, drywall to crack, and in severe cases, structural failure.

At Phoenix Home Remodeling, header sizing for any wall opening is confirmed with engineering documentation before construction begins. This is not a field decision made by the framing crew. It is a design decision that requires knowing the span, the load above, and the framing configuration.

Because the consequences of an undersized header develop slowly and are easy to miss until significant damage has occurred. An undersized header for a wide opening may perform adequately for years before the deflection becomes visible as cracked drywall above the opening, sticking doors, or sloping floors. By the time these symptoms appear, the header has often been deflecting for years. Replacing a header after walls are closed requires significant demolition and reconstruction work that costs far more than engineering the correct size from the start.

Span: The width of the opening is the primary driver of header size. Wider openings require deeper headers. As a general reference, a 4-foot opening might require a 4x6 header while an 8-foot opening requires a deeper member, but the actual engineering must account for the specific load conditions.

Load above: A header below a point load, such as a post from the floor above, a ridge beam, or a concentrated structural load, requires heavier sizing than a header carrying only the roof or ceiling load distributed over a wide area.

Material options: Headers are typically constructed from doubled dimensional lumber, LVL (laminated veneer lumber) beam, or PSL (parallel strand lumber). LVL and PSL beams are more dimensionally stable and can span greater distances than dimensional lumber of the same nominal size.

King studs and jack studs: The header rests on jack studs (also called trimmer studs) on either side of the opening, which transfer the header load to the floor. The king studs beside the jack studs provide lateral support. This framing assembly at each side of the opening is as important as the header itself.

Permit requirement: Any opening created in a load-bearing wall requires a permit in Phoenix and surrounding jurisdictions. The permit process includes plan review of the structural work. Engineering documentation for the header is part of the permit submission.

Only in load-bearing walls. In partition walls, which carry no structural load, an opening can be framed without a structural header, though a minimal header is still typically installed to provide a nailing surface for finish materials. The critical first step is confirming whether the wall is load-bearing before determining header requirements.

Experienced framers often use span tables for common residential conditions. However, for any opening wider than a standard door or in conditions with unusual loading, engineer-stamped documentation is the appropriate approach and is increasingly required by inspectors. In our projects, any structural opening has engineering documentation before framing begins.

Header sizing is part of our structural evaluation during the design phase. We coordinate with a structural engineer on any project that involves load-bearing wall modifications. The header type, size, and framing configuration are documented and included in our permit package. Our framing subcontractor builds to that specification, and the work is inspected before walls are closed.

• Is this wall load-bearing and how have you confirmed that?
• Who is engineering the header size for this opening?
• What material are you using for the header and why?
• Will this work be permitted and inspected before the walls are closed?
• What is the framing configuration at each side of the opening?

See also: Load-Bearing Wall, Blocking (Construction), Building Permit (Remodeling), Feasibility Assessment, Open Concept Kitchen, Scope of Work