Header Span Chart: Sizing Door, Garage and Bearing Wall Headers

Every opening in a wall interrupts studs that were carrying weight, and the header is what picks that weight up and moves it to the sides. A header span chart tells you what size header handles a given opening width under a given load, plus how many jack studs each end needs. The catch is that “given load” does a lot of work. A 6 foot opening in a non-bearing partition needs almost nothing, while the same opening under two floors and a roof may need a beam twice as deep.

To use a chart, you need three facts: the rough opening width, what the wall supports (roof only, roof plus one floor, or more), and the building width or snow load the table assumes. Then you match those to a header size and jack stud count. All sizes given here are typical examples meant to explain how the tables behave. Local code tables, the manufacturer’s tables for engineered headers, and an engineer or the building department govern the header you actually install.

Reading a Header Span Chart Step by Step

Residential code header tables and lumber association tables follow a similar pattern. Down the side you find header sizes such as 2-2×6, 2-2×8, 2-2×10 and 2-2×12 (the leading number is the count of boards). Across the top you find conditions: the ground snow load, the building width, and what the wall supports. Each cell lists the maximum span and the number of jack studs required at each end.

1. Measure the rough opening. Headers are sized for the opening, not the door slab. A 36 inch door usually needs a rough opening around 38 inches wide.
2. Decide what the wall carries. Look in the attic and basement. Joists or rafters landing on top of the wall, or a wall stacked directly above, mean it is bearing.
3. Find your building width. This is the depth of the house measured perpendicular to the ridge, often 24, 28, 32 or 36 feet in tables.
4. Pick the snow load column for your area. Your building department can tell you the ground snow load.
5. Read down to the first header whose listed span meets or beats your opening, and note the jack stud count.

Typical Examples by Opening Type

The figures here are illustrative, drawn from the general behavior of common lumber tables for a single-story house about 28 feet wide in a light snow area. They are examples, not design values. Your local code tables and an engineer govern.

Door Headers

Standard interior and exterior doors are the easy case. Most fall between 30 and 38 inches of rough opening, and in a bearing wall a doubled 2×6 or 2×8 usually covers it under light loads. In a non-bearing partition, many builders use a flat 2×4 or a single 2x header simply to give the drywall and trim something to fasten to. Even so, confirm the wall really is non-bearing before you go light.

Patio and Slider Headers

Patio doors and sliders run 5 to 8 feet wide and almost always sit in exterior bearing walls. This is the range where a 2×10 header span chart row starts to matter. A doubled 2×10 may cover a 6 foot slider under roof load alone, but stack a second floor on top and you are typically into doubled 2x12s or an engineered header. Two jack studs per side is common at this width.

Garage Door Headers

Single garage doors are 8 to 10 feet wide and doubles are usually 16 to 18 feet. Sawn lumber runs out of capacity quickly at those widths, especially in snow country or under a bonus room. Most builders switch to LVL or glulam, sized from the manufacturer’s tables. Wind uplift and racking also matter at large openings, and many jurisdictions require specific bracing beside garage doors.

Load-Bearing Wall Beam Span Tables

When you remove part of a bearing wall to open a kitchen or living area, the header becomes a beam, and a load bearing wall beam span table replaces the simple header chart. These tables usually ask for the tributary width (half the joist span on each side added together) rather than building width. They also tend to assume floor loads with tighter deflection limits, because a floor beam that flexes causes bounce and tile cracks.

A load bearing beam span table may also distinguish dropped beams, which sit below the joists, from flush beams, which sit in the plane of the joists with hangers. Flush beams look cleaner but need hangers rated for the load and often need more plies because headroom limits their depth. Long openings frequently need mid-span posts with their own footings. This is also the point where most building departments want an engineer’s letter or stamped drawings.

Single vs Double 2x, Built-Up and LVL Headers

• Single 2x headers: used in non-bearing walls or in some energy-efficient framing layouts where a single header sits at the top plate. Only use them where the code tables or an engineer allow.
• Double 2x headers: two boards on edge with a 1/2 inch spacer of plywood or rigid foam to match a 3-1/2 inch wall. The most common header in houses.
• Built-up triple headers: three boards for 2×6 walls or heavier loads. Nail or screw the layers together as the code specifies.
• LVL and other engineered headers: stiffer, straighter and less prone to shrinkage, so drywall cracks at corners are less common. Sized from the manufacturer’s tables.

Jack Stud and King Stud Counts

The jack stud count in a header span chart is not decoration. Jack studs (also called trimmers) sit under each end of the header and carry its load down to the bottom plate. Wider and heavier headers produce bigger end reactions, and one jack stud can crush or buckle under them. Tables commonly call for one jack on narrow openings and two or more on wider ones. King studs run full height beside the jacks and keep the wall straight; wide openings may need multiple kings for wind resistance.

Load must continue all the way down. If the jack studs land on a floor over a crawlspace or basement, there should be solid blocking or a beam under them, not just subfloor between joists. A header that is perfectly sized but bears on nothing solid will still sag.

Troubleshooting Header Problems

• Cracks at door corners: often shrinkage in sawn lumber headers or an undersized header deflecting. An engineered header usually solves the first; resizing solves the second.
• Doors that bind at the top: can signal header sag. Check whether the opening is wider than the header was sized for.
• Bowed top plate above an opening: missing jack studs or point loads from above.
• Header deeper than wall height allows: use a shallower engineered header with more plies, or reframe the opening lower.

Typical Cost Ranges

Lumber for a doubled 2x header is inexpensive, often under the cost of a dinner out for a door opening. LVL headers for patio and garage doors usually range from about a hundred dollars to several hundred depending on length and depth. The labor around the header is the bigger number: widening a bearing wall opening with shoring, new header, trim and drywall repair often runs from a couple thousand dollars to several thousand, and full bearing wall removals with engineering commonly run higher.

Structural Safety Tips

Build temporary shoring walls on both sides before cutting any stud in a bearing wall. Anchor posts and jack studs into solid framing, and carry loads to footings where needed. Garage and exterior openings may require straps or hold-downs for wind uplift. If a new post needs a footing, call 811 before digging. Exterior changes can also need HOA approval.

When to Call a Licensed Professional

Bring in a structural engineer and a licensed contractor for bearing wall removals, garage door headers under living space, any opening wider than roughly 8 feet in a bearing wall, and any time a post or girder lands on the header. Most towns require a permit for structural changes. Electrical, plumbing and HVAC runs inside the wall need licensed trades to reroute them safely.