Awaiting expert review. This page covers safety or regulatory rules that change over time. It is kept out of search results until a qualified reviewer has checked it; the sources below are dated so you can verify each point.
Quick answer
A structural header is a horizontal beam built into a load-bearing wall over a door, window or other opening, which picks up the weight from above and carries it sideways to studs or posts on each side of the opening.
Headers are sized by load, span and lumber grade. The 2021 IRC gives span tables for common wood headers; anything outside them, or any new or wider opening in a bearing wall, needs a design by a qualified professional.
Quick facts
The key facts about Structural Header, with sources:
Key takeaways
- A header is a short beam that bridges an opening in a load-bearing wall and passes the load to the studs beside it.
- Its size depends on the span, what it holds up, snow load, building width and lumber grade, not on the opening alone.
- The 2021 IRC gives prescriptive header span tables, but only for the conditions those tables list.
- Widening a door or window in a bearing wall is structural work: plan for an engineer, a permit and temporary shoring.
- Nonbearing walls do not need load-bearing headers, but a wall’s status must be confirmed first.
A header, in plain English
In a framed wall, studs stand side by side and carry weight straight down. Cut a hole for a door and you remove some of those studs.
The weight they carried still has to go somewhere. A header is the beam that sits over the hole and carries that weight sideways to the studs at each edge.
The U.S. Department of Energy’s Building America Solution Center describes it the same way: in load-bearing exterior walls, structural headers are placed over windows and doors to pick up the load from the building above and transfer it to the posts on both sides of the opening 2.
Headers are part of a chain. The roof or floor above rests on the wall, the header collects that load over the opening, the jack studs under each end carry it down, and the foundation takes it last.
Break any link and the load has nowhere safe to go. That is why headers matter most in a load-bearing wall.
How a header carries load
The load path below follows the IRC framing rules and DOE’s description of headers 12.
- Load arrives from above. Roof, ceiling and floor framing rest on the top plates of the wall.
- Cripples or plates carry it to the header. Short studs or the plate above the opening pass the load down to the header.
- The header bends a little and carries it sideways. Deeper and thicker headers bend less and can span farther.
- Jack studs take each end. The IRC tables list the number of jack studs needed at each end of a header; where one jack is required, an approved framing anchor to the full-height stud may be used instead 1.
- King studs and the wall below finish the path. The load goes down through the wall and floor framing to the foundation.
- Roof, ceiling or floor loadRests on the wall above the opening
- Top plate and cripplesBring the load down to the header
- HeaderSpans the opening and carries the load to each side
- Jack studs (trimmers)Number set by the IRC tables or the engineer
- Wall and floor belowCarry the load on down
- FoundationThe end of the load path
A header is one link in a continuous load path. Every link must be sized for the load. Source: [1] [2]
Because each part of the path is sized for the load above, a header that looks the same as its neighbor may be doing a very different job. A header under a roof girder or a floor beam can carry far more than one under a simple roof edge.
Types of headers
| Type | What it is | Where it is used |
|---|---|---|
| Built-up dimension lumber | Two to four 2x members nailed together, per Table R602.7(1) 1 | Most bearing-wall openings in houses |
| Single member header | One member framed with a flat 2x plate on top and bottom, per R602.7.1 1 | Openings within the Table R602.7(1) limits |
| Rim board header | Rim board sized per Table R602.7(1), supported by full-height studs, per R602.7.2 1 | Openings just under floor framing |
| Wood structural panel box header | Plywood or OSB skins over a framed box, per R602.7.3 1; APA details one- and two-sided versions 4 | Energy-efficient walls with room for insulation |
| Insulated header | Structural wood layers with rigid foam between or beside them 2 | Exterior walls where heat loss matters |
| Engineered beam | LVL, PSL or glulam sized by the maker’s tables or an engineer | Wide openings and heavy loads |
| Nonbearing header | A single flat 2x4 per R602.7.4 1 | Openings in walls that carry no load from above |
Header vs lintel vs beam
A header is a beam over an opening in a framed wall. A lintel does the same job in masonry. A beam is the general term for any horizontal member carrying load across a span, including girders that carry other framing.
Example: reading the IRC header span table for an exterior wall
This shows how to read one row set of 2021 IRC Table R602.7(1).
The house is an example; the spans are copied from the table for headers supporting roof and ceiling only, at 30 psf ground snow load, in a building 24 feet wide 1.
This is an illustration of how the table works, not a design. Your header must be sized by your designer or engineer for the real loads.
| Header size (No. 2 lumber) | Max span, roof and ceiling only, 30 psf snow, 24 ft wide | Jack studs per end |
|---|---|---|
| 2-2x6 | 4 ft 7 in | 1 |
| 2-2x8 | 5 ft 9 in | 1 |
| 2-2x10 | 6 ft 10 in | 2 |
| 2-2x12 | 8 ft 1 in | 2 |
| 3-2x10 | 8 ft 7 in | 1 |
| 3-2x12 | 10 ft 1 in | 2 |
| Example check: a 6 ft patio door | 2-2x10 (6 ft 10 in) works; 2-2x8 (5 ft 9 in) does not | Within these table conditions only |
Three lessons follow. First, a deeper header spans farther. Second, the same header spans less in a wider building or under more snow, so the table has nine columns for each size.
Third, the table covers only the conditions in its notes, such as No. 2 grade of four common species and a top braced by framing above 1.
Headers that also carry a floor, a girder or a point load use other rows or an engineered design.
Where headers show up in a remodel
On plans. Drawings for a new or wider opening in a bearing wall label the header size and material, such as "(2) 2x12" or "LVL," along with jack studs and any posts below.
Plans for a kitchen remodel that opens a wall to a dining room will show a header or beam at the new opening.
On a quote. A bid for a new patio door or wider window in an exterior wall should say who sized the header, what it is made of, and whether temporary shoring is included.
At inspection. The framing inspection checks headers and jack studs before the wall is closed. The order of inspections is covered in our permits and approvals guide.
In the energy details. DOE’s code brief notes that since the 2009 codes, header cavities should be insulated, filled with material of at least R-3 per inch 3.
Ask "who sized it?"
If a quote lists a header size, ask whether it came from the IRC table for your exact conditions or from an engineer’s calculation. Either can be right, but someone should be able to show the source.
What a properly sized header does, and its limits
What it does
- Lets you have doors and windows in bearing walls without losing strength.
- Keeps load off window and door frames, which are not built to carry it.
- Right-sized headers leave room for insulation; DOE notes many headers are oversized 2.
- Prescriptive tables let common openings be framed without custom design 1.
What it cannot do
- Carry loads outside the table conditions without design.
- Fix a weak load path below, such as a missing jack stud or undersized post.
- Stop heat flow; solid wood headers are a thermal weak spot 2.
- Be enlarged in place; a wider opening means a new header.
Limits of the prescriptive tables
The IRC header tables are powerful but narrow. Table R602.7(1) assumes No. 2 grade Douglas fir-larch, hem-fir, Southern pine or spruce-pine-fir, and it assumes the top of the header is braced by framing above.
Where the header is not braced, for example where cripple studs bear on it, the notes reduce the allowed spans 1.
The table also covers specific loads: roof and ceiling, or roof and ceiling plus one or more floors, at listed snow loads and building widths 1.
A header under a girder, a point load from a post, or a wall in a high-wind or seismic area may fall outside it. Those cases need an engineered design.
Finally, older homes may not match modern assumptions. Old-growth lumber, past remodels and hidden damage change what is really there. A licensed engineer is the right person to judge an existing header.
What drives the cost of header work
We do not publish prices. The cost of a new or replaced header depends on the opening width, the load above, the header material (dimension lumber vs engineered beam), whether temporary shoring walls are needed, whether utilities in the wall must be moved, and the finish work to patch drywall, siding and trim.
Engineering and permit fees are part of the budget, not extras.
Hidden conditions are the main risk. Opening a wall can reveal an undersized old header, rot or missing jack studs, which adds work. Hold a contingency, as our remodeling cost guide explains, and use the quote comparison tool to check that each bid includes the same structural scope.
A properly sized and protected header has no set lifespan; it lasts as long as the wall stays dry and unaltered.
How a new or wider opening in a bearing wall is done
This is structural work. The steps below describe what licensed professionals do under a permit, so you know what to expect and what to ask for.
- Confirm whether the wall is load-bearing and what it carries; this takes a qualified professional, not a guess.
- Have the header and posts sized from the IRC tables for your exact conditions, or designed by a licensed engineer.
- Apply for a building permit; our permit checker can help you start.
- Install temporary shoring to carry the load while studs are removed.
- Frame the new opening: king studs, jack studs (or approved hangers), header and cripples per the design 1.
- Insulate and air seal header cavities in exterior walls 3.
- Pass the framing inspection before drywall, siding or trim close the wall.
Protecting headers over time
Headers need no service, but they need to stay dry and untouched.
- Keep window and door flashing in repair; leaks at the head of a window soak the header first.
- Never notch or drill a header for wires, pipes or ducts without design approval.
- Do not add loads above an opening, such as a new beam or heavy equipment, without a check.
- Watch for changes after nearby work: new cracks at door corners are worth a look.
- Keep records of header sizes from plans or inspection photos.
Warning signs of a failing or undersized header
- Doors or windows that start to stick or bind at the top.
- Diagonal cracks in drywall or plaster from the top corners of openings.
- A visible sag in the wall or ceiling line above an opening.
- Gaps opening between trim and wall at the head of a door or window.
- Rot or water stains at the head of a window or door.
Do not cut a bearing wall without a design
Removing studs from a load-bearing wall without temporary shoring and a sized header can drop the structure above. Have a licensed engineer or qualified professional confirm the wall, size the header and specify shoring, and get a permit. In pre-1978 homes, cutting painted walls is also lead-safe work for an EPA RRP-certified firm 5.
Any of these calls for a licensed structural engineer or an experienced framing contractor to look before more damage occurs. Do not jack or shore a sagging header yourself.
Code rules for headers: 2021 IRC and local adoption
Authority and edition. The rules below are from the 2021 International Residential Code (IRC), published by the International Code Council. States and cities adopt the IRC on their own schedule and may amend it, and work on existing homes may also fall under the International Existing Building Code. Your building official decides what applies.
Span tables (R602.7). Section R602.7 points to Tables R602.7(1), R602.7(2) and R602.7(3) for header spans.
Table R602.7(1) covers girders and headers in exterior bearing walls, with spans by size, ground snow load (30, 50 and 70 psf) and building width (12, 24 and 36 feet), and the number of jack studs at each end 1.
Table notes. Spans assume No. 2 grade Douglas fir-larch, hem-fir, Southern pine and spruce-pine-fir; building width is measured perpendicular to the ridge and may be interpolated.
Where one jack stud is required, an approved framing anchor to the full-height stud may be used instead; and the 30 psf column applies where ground snow load is lower and roof live load is 20 psf or less 1.
Other header forms. R602.7.1 covers single member headers, R602.7.2 rim board headers supported by full-height studs, and R602.7.3 wood structural panel box headers per Table R602.7.3 1.
Nonbearing walls (R602.7.4). Load-bearing headers are not required in interior or exterior nonbearing walls; a single flat 2x4 may serve over openings up to 8 feet wide if the distance to the parallel nailing surface above is not more than 24 inches 1.
Header vs. related framing members
| Member | What it does | Main difference from a header |
|---|---|---|
| Structural header | Spans an opening in a bearing wall 2 | The baseline |
| Jack (trimmer) stud | Holds up the end of a header 1 | Vertical; part of the header’s support |
| King stud | Full-height stud beside the jack | Runs plate to plate; anchors the opening |
| Engineered wood beam | Manufactured beam such as LVL | Often used as a header for wide or heavy openings |
| Roof truss | Engineered roof frame | Bears on the wall; its reactions may land on a header |
| Girder | A beam carrying other framing 1 | Shares Table R602.7(1) with headers but carries larger loads |
Myths about headers
- Myth Bigger is always better.
- Reality DOE notes many headers are overdesigned, which wastes wood and leaves no room for insulation 2; size to the load.
- Myth Every opening needs a big header.
- Reality Nonbearing walls do not need load-bearing headers under the IRC 1.
- Myth A doubled 2x12 works anywhere.
- Reality Its allowed span changes with snow load, building width and what it carries; the IRC table lists nine spans for that one size 1.
- Myth The window frame helps hold up the wall.
- Reality Window and door frames are not built to carry wall loads; the header and jack studs do that 2.
- Myth You can widen an opening by adding a stud to the old header.
- Reality A wider opening needs a new header sized for the new span, and a permit.
How snow load changes header size
Ground snow load is the regional variable built into the IRC header table. Table R602.7(1) gives separate spans at 30, 50 and 70 psf ground snow load 1.
For a doubled 2x10 carrying roof and ceiling only in a 24-foot-wide building, the allowed span is 6 ft 10 in at 30 psf, 5 ft 11 in at 50 psf and 5 ft 3 in at 70 psf 1.
Snow loads come from your jurisdiction’s design criteria; areas above 70 psf, and high-wind or seismic zones, typically need engineered headers. Ask your building department for the local design values.
When headers should shape your plan
Headers come into play whenever you add a door or window, widen an opening, open a wall between rooms or remove a wall. In a whole-home renovation they often decide what layouts are affordable.
If the wall is confirmed nonbearing, the header choice is simple. If it is bearing, or nobody is sure, plan for an engineer’s review, a permit and shoring before design is final.
Your next step: before you fall in love with a new opening, ask a professional to confirm the wall and estimate the header and post work.
- If New or wider opening in a load-bearing wall
- Then Yes; size from the IRC table for your conditions or by an engineer
- If Header must carry a floor, girder or point load
- Then Check the matching table rows or get an engineered design
- If Opening in a confirmed nonbearing wall
- Then No load-bearing header needed; flat 2x4 within limits
- If Not sure whether the wall is bearing
- Then Stop and have a qualified professional confirm first
Questions about Structural Header
What is a header in construction?
A header is a horizontal beam over a door, window or other opening in a framed wall. In a load-bearing wall it carries the weight from above across the opening to jack studs or posts on each side. In a nonbearing wall, the IRC does not require a load-bearing header.
How do I know what size header I need?
It depends on the span, what the header carries, the snow load, the building width and the lumber grade. The 2021 IRC Table R602.7(1) gives spans for common cases, but only within its stated conditions. For anything outside the table, or when unsure, have a licensed engineer size it.
Do interior doors need a header?
Only if the wall is load-bearing. The 2021 IRC says load-bearing headers are not required in nonbearing walls and allows a single flat 2x4 over openings up to 8 feet wide if the distance to the nailing surface above is 24 inches or less. A bearing interior wall needs a sized header.
What is the difference between a jack stud and a king stud?
A jack stud, also called a trimmer, sits under the end of the header and holds it up. A king stud runs full height from bottom plate to top plate beside the jack stud. The IRC tables list how many jack studs each header end needs.
Can I widen a window opening myself?
Widening an opening in a bearing wall is structural work. It needs a header sized for the new span, temporary shoring while studs are removed, and in most places a permit and inspection. Have a licensed engineer or qualified contractor plan it.
What is an insulated header?
An insulated header uses structural wood layers with rigid foam between or beside them, so the header area loses less heat. DOE’s Building America Solution Center notes many headers are oversized and that right-sizing them leaves room for insulation. ENERGY STAR sets minimum header insulation for its certified homes.
What is a box header?
A box header uses plywood or OSB skins nailed over a framed box above an opening. The 2021 IRC covers wood structural panel box headers in Section R602.7.3 with their own span table, and APA publishes one- and two-sided box header details for advanced framing.
What are signs of a failing header?
Look for doors or windows that start to stick at the top, diagonal cracks running from the top corners of openings, a sag in the wall or ceiling above, and rot at the head of a window. Have a structural engineer inspect before making repairs.
Do I need a permit to replace a header?
In most jurisdictions, yes. Replacing or adding a header in a bearing wall is structural work that typically needs a building permit and a framing inspection. Rules vary by city, so check with your building department before work starts.
Sources
- ICC, 2021 International Residential Code, Chapter 6 Wall Construction (R602.7, Table R602.7(1) and notes, R602.7.1–R602.7.4), retrieved .
- U.S. DOE Building America Solution Center (PNNL), Advanced Framing: Insulated Headers, retrieved .
- U.S. DOE Building America Solution Center (PNNL), Insulating and Sealing Structural Headers: Code Compliance Brief, retrieved .
- APA – The Engineered Wood Association, One-Sided Wood Structural Panel Box Header (Typical Detail DT-AF-8), retrieved .
- U.S. EPA, Lead Renovation, Repair and Painting Program, retrieved .
Expert review
Written by the HyreRemodel Research team. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: Header rules, span-table values and notes were read from 2021 IRC Section R602.7, Table R602.7(1) and Sections R602.7.1 to R602.7.4 on ICC Digital Codes.
The load path and insulated-header guidance come from the DOE Building America Solution Center; the box header form from APA’s typical detail.
Spans in the example and chart are copied from the IRC table as an illustration of how to read it, not as a design.
This page is held noindex until a licensed structural engineer or building official reviews it. No prices are given.
Suggest a correction. We fix errors and say what changed.