What size header do I need for 8′, 10′ 12′ 14′, and 16′ garage door?

 Are you considering building a garage? If so, you’ve probably found yourself pondering a couple of crucial questions: “What size header do I need for my garage door, and what should be the rough opening dimensions?”

These questions are vital because they lay the foundation for a properly functioning garage, and today, we’re here to provide you with comprehensive answers.

In our previous discussion, we delved into the intricacies of rough opening sizes for garage doors.

Today, we’re shifting our focus to an equally essential aspect of garage door construction: the header size.

The Importance of a Garage Door Header

Before we dive into the nitty-gritty details of header sizes for different garage door widths, let’s understand the fundamental role of a garage door header.

Think of it as the unsung hero of your garage door setup. This horizontal beam, typically crafted from timber or Laminated Veneer Lumber (LVL), is strategically placed between two walls. Its mission?

To shoulder the weight of the structure above it and transfer that load seamlessly into the supporting walls.

In essence, the header ensures that your garage door and its surrounding structure remain sturdy and reliable.

Plus, it enables the walls to distribute all this weight safely into the foundation through the trusty plinth beam.

Now, let’s embark on our journey to demystify header sizes for garage doors of varying widths.

Factors Influencing Garage Door Header Size

Several factors influence the size of the header needed for your garage door installation:

Door Width: The width of the garage door is a key determinant of the required header size. Larger doors typically require larger headers to support their weight adequately.

Material: The material used for the header also affects its load-bearing capacity. Common materials include wood, steel, and engineered lumber like laminated veneer lumber (LVL).

Local Building Codes: Building codes vary by region and may stipulate specific requirements for garage door headers based on factors such as wind load, snow load, and seismic activity.

Roof Load: The weight of your roof applies constant pressure on the header. Accurately calculating this load is crucial for determining the header’s capacity.

Wind and Snow Loads: Areas prone to strong winds or heavy snowfall require headers capable of withstanding these forces. Considering wind and snow loads ensures the structural integrity of your garage door.

Floor Framing: Sometimes, the header supports the weight of the floor framing above. It’s important to account for this additional load in the header size calculation.

Choosing the Right Garage Door Header Size

Now that we understand the factors influencing garage door header size, let’s explore how to choose the right dimensions for your project:

1. Measure the Door Opening: Start by accurately measuring the width of the door opening. This measurement will serve as the basis for determining the required header size.

2. Consult a Size Chart: Utilize a garage door header size chart to determine the appropriate dimensions based on the width of your door opening. These charts provide guidance on the recommended header size for various door widths and construction materials.

3. Use a Calculator: If you prefer a more precise approach, consider using a garage door header size calculator. These tools take into account factors such as door width, material, and local building codes to recommend the optimal header size for your project.

4. Consider LVL Headers: For larger garage doors or applications where space is limited, consider using laminated veneer lumber (LVL) for the header. LVL offers greater strength and load-bearing capacity than traditional lumber, allowing for smaller header dimensions without sacrificing structural integrity.

Adding an opening into an existing wall for Garage Door

Adding an opening to an existing wall requires meticulous planning, especially when dealing with load-bearing structures. In this guide, we’ll delve into the essential considerations and address common concerns to ensure a successful project.

Understanding Load-Bearing Walls: Your existing wall supports significant weight, including trusses, making it a crucial component of your home’s structural integrity. Before proceeding, it’s essential to determine the load-bearing capacity and potential impacts of alterations.

Assessing Load Requirements: Consulting local building codes and regulations is imperative. Consider factors like snow load, seismic activity, and specific requirements for your region to ensure compliance. Seeking guidance from a qualified engineer can provide invaluable insights tailored to your project’s needs.

Selecting the Right Header Size: Determining the appropriate header size is crucial for supporting the new opening. Referencing header span tables and consulting with professionals can help you make informed decisions. Consider options like laminated veneer lumber (LVL) for added strength and stability, especially for maximizing headroom.

Addressing Load Transfer: Apart from supporting the load across the span, it’s essential to ensure proper load transfer into the soil. Assess the foundation and floor slab to prevent structural issues like sinking or fracturing. Engage with local engineers to understand soil conditions and implement suitable load transfer mechanisms.

Ensuring Structural Integrity: Incorporate measures like fire stops and horizontal studs to enhance structural stability and prevent load-induced twisting or shifting. Pay attention to details like power and plumbing passage through the joining plane, ensuring functionality and avoiding potential issues.

Addressing Exterior Concerns: Consider external factors like eave design and water management. Properly designed eaves and gutter systems can mitigate issues like wind-driven rain splatter and water damage, ensuring the longevity of your structure.

Standard Header Size for Garage Doors

First and foremost, it’s essential to establish a baseline. The standard size for a garage door header dictates that it should be 9 inches longer than the width of the door. This allows ample space for proper support. As for the depth of the header, which is typically an LVL (Laminated Veneer Lumber) beam, it should be a minimum of 8 inches. And don’t forget the garage door thickness; it should measure 4 inches. These dimensions are tailored specifically for garage doors, which tend to be more substantial than your average household door.

Now, let’s delve into the specifics for various garage door widths:

For an 8-Foot Garage Door

If your garage door spans 8 feet in width, you’ll need two headers, each measuring 2 inches in width and 8 inches in depth. Be sure to make these headers at least 9 inches longer than the door itself (which is 8 feet) for optimal support.

For a 9-Foot Garage Door

When dealing with a 9-foot-wide garage door, you should opt for two headers that are 4 inches wide and 10 inches deep. These headers should be precisely 9 feet 9 inches in length to ensure your wider door receives the necessary support. Remember, garage doors are broader than standard doors, so their headers should meet higher specifications.

For a 10-Foot Garage Door

For those with a 10-foot-wide garage door, follow this rule of thumb: you’ll require two headers, each measuring 4 inches in width, 10 inches in depth, and with a length of 10 feet 9 inches. This setup, made from timber or LVL, will provide your door with the strength it needs.

For a 12-Foot Garage Door

Moving on to 12-foot-wide garage doors, you’ll want to use two 2×12 size headers, each with a minimum length of 12 feet 9 inches. However, we recommend going the extra mile and using 12 inches longer headers, measuring around 13 feet. Keep the header depth at a minimum of 12 inches, with a width of 4 inches to meet the necessary standards.

For a 14-Foot Garage Door

A 14-foot-wide garage door calls for two 2×12 headers crafted from timber or a single 2×12 header constructed from LVL. Ensure that the header length is at least 12 inches longer than the door’s width for proper support.

For a 16-Foot Garage Door

With a 16-foot-wide garage door, you should invest in a header that’s a minimum of 17.6 feet long, with a depth of at least 12 inches and a width of 5.25 inches. These specifications will guarantee the stability of your garage door setup.

For an 18-Foot Garage Door:

For those ambitious 18-foot-wide garage doors, you’ll need a header that’s a minimum of 20 feet in length. Keep the header depth at 12 inches and the width at 5.25 inches to meet the necessary standards.

For a 20-Foot Garage Door:

Finally, if your garage boasts a 20-foot-wide door, you should aim for a header that’s at least 22 feet long. However, we strongly recommend going a step further and using a 23-foot-long header for added support. The header’s depth should be a minimum of 14 inches, with a width of at least 5.25 inches to accommodate the substantial size of the door.

These guidelines are vital to ensure that your garage door setup remains sturdy, safe, and reliable. Getting the right header size is a crucial step towards the successful construction of your garage. By adhering to these specifications, you’re not only ensuring the structural integrity of your garage door but also guaranteeing the long-term functionality and safety of your entire garage.

Garage door header size chart


How thick should a garage header be?

The thickness of a garage header depends on factors like the width of the door and local building codes. Generally, for standard residential doors, a header thickness of 2×6 inches or 1 ¾ inches is common. However, for larger or heavier doors, a thicker header may be needed for added support.

What size should a door header be?

The size of a door header varies depending on the width of the door and the load it carries. Typically, for standard residential garage doors, a header made from 2×12 inches lumber is sufficient. However, for larger doors or when local building codes require it, a larger header may be necessary.

Do garage doors have headers?

Yes, garage doors typically have headers installed above the door opening. The header provides support for the weight of the door and helps distribute the load evenly to the surrounding structure. It is an essential component of the garage door assembly, ensuring proper functionality and structural integrity.

What size header beam do I need?

The size of the header beam needed depends on factors such as the width of the door, the material used, and local building codes. It’s recommended to consult a size chart or use a calculator to determine the appropriate header size based on these factors. In general, larger doors or doors made from heavier materials will require a larger and stronger header beam for adequate support.


Popular posts from this blog

LVL beam span calculator

What size LVL to span 30 feet (with Calculator)