How to Build a Header for a Garage Door: Types, sizing, step-by-step how-to process
A complete, code-aware guide covering the definition, types, sizing, step-by-step how-to process, safety, cost, advantages, disadvantages, and frequently asked questions about the garage door header.
Why Is a Garage Door Header Important?
Without a properly sized header, the wall above a garage door opening has nothing to carry its weight, which can lead to sagging, cracked drywall or siding, a binding garage door, or in severe cases, structural failure. A correctly engineered header:
- Transfers roof, snow, and wind loads safely around the opening.
- Keeps the garage door track straight and functioning smoothly.
- Meets local building code requirements for load-bearing openings.
- Protects the long-term structural integrity of the entire garage wall and roof system.
Types of Garage Door Headers
The right header type depends on the span of the opening, the load above it, and budget. Here are the most common options used in residential and light commercial construction:
Solid-Sawn Header
A single piece of dimensional lumber (e.g. a 4×8 or 4×10). Simple and inexpensive, but limited in span and prone to warping over time.
Built-Up Header
Two or three pieces of 2x lumber sandwiched with 1/2 inch plywood spacers to match wall thickness. Economical and widely used for standard single-door openings.
LVL (Laminated Veneer Lumber)
Factory-engineered beam with high strength-to-depth ratio. Straighter and stronger than dimensional lumber, ideal for wider double-door openings.
Steel I-Beam / Flitch Beam
Used for very wide spans or heavy loads above (such as a second story). A flitch beam sandwiches steel plate between wood members for extra strength.
Concrete or Steel Lintel
Used above garage openings in block or brick walls; precast concrete or steel angle lintels carry the masonry load above the opening.
Box Header / Header-Truss
An engineered, hollow-core header truss offering a lightweight alternative with good insulation value for non-load-bearing or lightly loaded walls.
How to Build a Garage Door Header (Step-by-Step)
This general sequence reflects standard framing practice. Always confirm sizing and local requirements before starting, and stop and consult a professional if the wall is load-bearing and you are unsure of the correct load path.
Measure the Opening and Confirm the Load Path
Measure the rough opening width and identify whether the wall is load-bearing. Check the framing above for roof rafters, trusses, or a second-story floor bearing directly on the wall.
Calculate the Required Header Size
Use a prescriptive span table (see below) or a structural engineer’s calculation based on the tributary load, snow load, and species/grade of lumber.
Install Temporary Shoring
Before removing any wall studs, build a temporary shoring wall or set jack posts on both sides of the opening to safely carry the load overhead.
Frame King Studs and Jack Studs
Install full-height king studs at the outer limits of the new opening, and jack studs (trimmer studs) inside them to support the header ends at the correct rough opening height.
Build and Set the Header
Assemble a built-up header (lumber plus plywood spacer) or set a single LVL/steel beam cut to the exact opening width, then lift it into place on top of the jack studs.
Fasten the Header and Add Cripple Studs
Secure the header with structural screws, framing nails, and metal hurricane ties or hangers as required by code. Fill the space above the header with cripple studs up to the top plate.
Remove Shoring, Inspect, and Finish
Once the header is fully fastened and load has transferred through the new framing, remove the temporary shoring. Schedule a code inspection, then install flashing, siding repairs, and the garage door track.
Garage Door Header Span Table (General Reference)
The table below is a simplified, illustrative reference for a single-story wall under typical residential loading. Real-world spans vary with lumber species, grade, snow load, and wall height, so always verify against your local building code table or an engineer’s calculation.
| Header Type | Approx. Max Span | Typical Use |
|---|---|---|
| 2 – 2×6 built-up | 4′-9″ | Small utility door |
| 2 – 2×8 built-up | 6′-2″ | Single walk door |
| 2 – 2×10 built-up | 7′-5″ | Narrow single garage door |
| 2 – 2×12 built-up | 8′-7″ | Standard 8’–9′ garage door |
| 3.5″ x 9.25″ LVL | 10′-6″ | Wide single garage door |
| 3.5″ x 11.875″ LVL | 13′-6″ | Standard 16′ double garage door |
| Steel / flitch beam | 16’+ | Wide double door, heavy load above |
Figures are general planning estimates, not a substitute for a stamped engineering calculation or your local IRC/IBC prescriptive table.
Is It Safe to Build Your Own Garage Door Header?
⚠ Read Before You Start
Building a header can be done safely by an experienced DIYer for small, code-table-covered spans, but it involves real structural risk. Keep these safety points in mind:
- Never remove studs from a load-bearing wall without temporary shoring in place first.
- Confirm header size against a verified span table or engineer’s letter — undersizing risks sagging or collapse.
- Most jurisdictions require a building permit and inspection for any load-bearing wall alteration, including garage door headers.
- For spans wider than roughly 6–8 feet, second-story loads, or unusual roof framing, hire a licensed contractor or structural engineer.
- Wear safety glasses, gloves, and use proper lifting technique or a second person when setting heavy beams.
Advantages and Disadvantages of a Garage Door Header
Advantages
- Allows a wide, functional vehicle opening without sacrificing structural support.
- Properly sized headers offer decades of reliable performance.
- Engineered options (LVL, steel) provide straighter, more stable beams than solid lumber.
- Improves resale value by supporting code-compliant garage conversions or widened doors.
Disadvantages
- Engineered beams and steel options can be costly compared to standard framing.
- Requires temporary shoring, which adds labor time and complexity.
- An undersized header is a serious safety risk and may not be visible until years later.
- Permit and inspection requirements can extend project timelines.
- Oversized headers can reduce ceiling or door clearance (headroom).
Common Uses of Garage Door Headers
- Standard single garage door openings (8–9 feet wide).
- Double garage doors (16 feet wide), typically requiring an engineered beam.
- Widening an existing garage door opening during a remodel.
- Converting a standard wall section into a new garage entrance.
- Carports, workshops, pole barns, and detached garages.
- Any load-bearing wall opening where a window, door, or passage interrupts the studs.
How Much Does It Cost to Build a Garage Door Header?
Costs vary widely by region, header type, and whether the project is DIY or professionally installed. General planning ranges:
Wider double-door spans, steel beams, and second-story loads push costs toward the higher end, or beyond it in some markets.
Building Codes and Permits
In the United States, header sizing for wood-frame walls is commonly governed by IRC Section R602.7 (Headers), which provides prescriptive span tables for standard loading conditions. Most local building departments require:
- A submitted permit application before altering a load-bearing wall.
- Framing sized to match the local prescriptive table, or a stamped engineering letter for non-standard spans.
- A framing inspection before the wall is closed up with drywall or siding.
Requirements vary by state, county, and city, so always confirm with your local building department before starting work.
Frequently Asked Questions
It is a structural beam above the opening that carries the wall, roof, and any floor load, transferring weight around the door and down into the king studs and foundation.
Thickness depends on span and load. Built-up wood headers usually match wall thickness (about 3.5 inches), while LVL beams commonly range from 3.5 to 7 inches. Confirm with a span table or engineer.
Smaller, code-table spans can often be handled by an experienced DIYer with proper shoring. Wider spans or second-story loads are best left to a licensed contractor or structural engineer.
Most jurisdictions require a permit and inspection for any load-bearing wall modification, including header installation.
A 16-foot opening almost always needs an engineered LVL or steel beam rather than dimensional lumber; get a stamped calculation for this span.
Header is the common term in wood framing; lintel usually refers to the same function over a masonry or concrete opening. Both carry load across the opening.
Roughly $300–$1,500 in materials for a DIY project, or $1,500–$4,000+ with professional labor, shoring, and permits, depending on span and region.
A doubled 2×12 built-up header can typically span roughly 7 to 9 feet under common loads, suiting many single garage door openings.
Not always for small, table-covered spans, but strongly recommended, and often required, for wide openings, unusual loads, or second-story walls.
A single-door header replacement can often be framed in one day; wider or engineered-beam projects can take two to three days.