What is a Door Header?
A door header (also called a lintel) is a horizontal structural member that spans the top of a door or window opening in a framed wall. Its purpose is to transfer the load from above the opening to the jack studs on either side, which carry the load down to the foundation. Without a properly sized header, the weight of the structure above would cause the opening to sag or collapse. Headers are required in all load-bearing walls and are recommended even in non-bearing walls for structural integrity.
The size of the header depends on the span width, the load being carried, and the building code requirements. For residential construction, the International Residential Code (IRC) provides prescriptive header sizing tables that simplify the design process. For commercial or unusual residential situations, an engineer should calculate the specific header requirements based on actual loads.
Header Sizing Guide
General rules of thumb for header sizing in residential load-bearing walls supporting one floor and a roof:
4 to 6 ft span: Double 2x8
6 to 8 ft span: Double 2x10
8 to 10 ft span: Double 2x12
Over 10 ft: Engineered lumber (LVL)
Header Size Table
| Span | Non-Bearing | Bearing (1 story) | Bearing (2 stories) |
|---|---|---|---|
| Up to 3 ft | Double 2x4 | Double 2x6 | Double 2x8 |
| 3-4 ft | Double 2x4 | Double 2x6 | Double 2x10 |
| 4-6 ft | Double 2x6 | Double 2x8 | Double 2x12 |
| 6-8 ft | Double 2x6 | Double 2x10 | LVL Required |
| 8-10 ft | Double 2x8 | Double 2x12 | LVL Required |
| 10-12 ft | Double 2x10 | LVL Required | LVL Required |
Header Construction Methods
Standard headers are built by sandwiching a piece of 1/2-inch plywood between two pieces of dimensional lumber, creating a header that matches the wall width (3.5 inches for 2x4 walls). For 2x6 walls, three layers of lumber or an LVL beam with filler is used to match the 5.5-inch wall depth. The plywood filler provides shear resistance and makes the total header width match the stud depth exactly.
Worked Example
A 3-foot wide door opening in a load-bearing wall supporting one story above:
Header length = 3 ft + 3" (each side) = 3'-6"
Jack studs: 2 (one per side)
King studs: 2 (one per side)
Frequently Asked Questions
Do non-bearing walls need headers?
Technically, non-bearing walls do not require structural headers since they carry no load from above. However, most builders install at least a flat 2x4 header (turned on its side) to provide a nailing surface for drywall and door trim. Building codes in many jurisdictions require a minimum header even in non-bearing walls.
What is a jack stud vs. a king stud?
Jack studs (also called trimmer studs) are shorter studs that sit directly under each end of the header and support its weight. King studs run full height from the bottom plate to the top plate, flanking the jack studs on the outside. Together, they create a rigid frame that carries the header load to the bottom plate and foundation.
When should I use an LVL header?
Laminated veneer lumber (LVL) headers are used when the span exceeds what dimensional lumber can handle (typically over 8-10 feet for load-bearing walls), or when the load is unusually heavy. LVL headers are stronger, straighter, and more consistent than dimensional lumber. They come in standard depths matching dimensional lumber sizes and can span significantly further.
How do I determine if a wall is load-bearing?
Load-bearing walls run perpendicular to the floor/ceiling joists above and carry structural loads to the foundation. Exterior walls are almost always load-bearing. Interior walls running parallel to the joists are typically non-bearing. When in doubt, consult the building plans or a structural engineer before cutting any wall opening.