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.

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

Garage Door Size	Garage Door Header size
8 Foot	2 2×8
9 Foot	2 2×10
10 Foot	2 2×10
12 Foot	2 2×10
14 Foot	2 2×12
16 Foot	2 2×14
18 Foot	2 2×16
20 Foot	2 2×20