Rough opening for a garage door of sizes 16′, 18′, 8′, 9′, 10′, 12′

Few weeks back, I’ve just managed to complete my garage door replacement project and I though it’s worth sharing my experience of how do you measure for garage door in the right fashion. A lot of homeowners are confused about terms like rough opening, rough framing, and finished opening.

The process might simple like just measuring rough opening of a garage door. But in reality, apart from width and height of rough opening; you need to measure headroom, side room, as well as backroom.

Table of Contents

What is rough opening?

In general framing concepts, rough opening is a size of opening that accounts for adjusting door or window in the position.

So, the size of rough opening is larger than the standard dimension of doors and windows. The main reason behind this difference is that rough opening also includes framing and space for shimming.

Different countries use different size of doors and windows and according to the size and type of opening the rough opening is selected.

Lumber Needed to Frame a Garage - O...
Lumber Needed to Frame a Garage - October 20, 2022

For simple doors and windows, the rough opening width is taken 2” more than width of door and window. Similarly, height is taken 1.5” more than the height of door and window.

Read here about rough opening size of common interior and exterior doors. Rough opening of doors

Rough opening

Rough opening or rough framing is the size of the opening before installing the finished framing. So, rough opening is all about leaving room for the frame and has to be larger than the size of your garage door.

Rough Opening for garage doors
Rough Opening for garage doors

Finished opening

After you’ve finished installation of framing, the remaining space left is the finished opening. The finished opening can be same or slightly smaller than the size of the garage door.  So, if you’re going to buy a garage door of 16×7 feet; the finished opening should also be 16×7 feet.

A garage door of different sizes is used in different countries depending upon the width of vehicle and number of vehicles to park. The size of garage door is larger than the simple doors.

Rough width of opening

Rough opening for garage door should be 3” wider than the width measured between left and right edges. For example, if we want to install a 10 feet wide door then we will have to provide 10 feet and 3-inch-wide rough opening.

Rough height of opening

For height of garage door, the rough opening should be 1.5” more than the distance measured from garage floor to top rough header. For example, if the height of door is 8 feet, then rough opening for height of garage door will be 8 feet and 1.5 inch. It’s the height you must manage before you can add framing elements.

The header at the top goes along wider than the door by as much as 9 inches.

Common sizes of garage doors

The garage door size varies according to a place where we live. But the most common size which is used for single car parking is 8’ wide and 7’ tall.

Similarly for double car parking the most common size used is 16’ wide and 7’ tall. The height of garage door normally varies from 7’ to 9’ according to the condition and suitability.

For installation of all sizes of garage door the adjustment for framing and shimming is done while providing opening to avoid size issue of door.

The common sizes which are mostly used for garages are 8’, 9’ ,10’ ,12’, 16’ ,18’ wide. The rough opening for doors will be different than this size of door.

Also Read: Types of doors

Rough openings for different size garage doors

For all size of garage door, the rough opening will be calculated by adding 3” on width of door and 1.5” will be added to height of door.

Rough opening for 8’ garage door

8’ wide garage door is the normal size which is used more commonly for garages. The height of this door usually varies from 7’ to 8’. The rough opening of this garage door is calculated by adding 3” in 8’ wide door and 1.5” in height of door.

For 7’ height of door

For 8’ height door

  • Height of door= 8’
  • Height added for rough opening= 1.5”
  • Height of rough opening = 8’+1.5”
  • Height of rough opening= 8’1.5”

  Rough opening for 9’ garage door

 9’ wide garage door size is also used more commonly for garages. The height of this door usually varies from 7’ to 8’. The rough opening of this garage door is calculated by adding 3” in 9’ wide door and 1.5” in height of door.

Rough opening for 10’ garage door

For 10’ garage door the rough opening will be calculated by adding 3” to width of door which is 10’ wide and 1.5” will be added to height of door. The height of door varies from 7’ to 8’ depending upon the type of vehicle and suitability for garage.

  • Width of door= 10’
  • Width added for rough opening= 3”
  • Width of rough opening= 10’+ 3”
  • Width of rough opening= 10’3”
  • Height of door= 7’
  • Height added for rough opening= 1.5”
  • Height of rough opening = 7’+1.5”
  • Height of rough opening= 7’1.5”

Rough opening for 12’ garage door

The selection of garage door depends upon the size of vehicle. For wider vehicles and large space this size is more suitable. For 12’ garage door the rough opening will be calculated by adding 3” to width of door and 1.5” will be added to height of door. The height of door varies from 7’ to 8’ depending upon the type of vehicle and suitability for garage.

  • Width of door= 12’
  • Width added for rough opening= 3”
  • Width of rough opening= 12’+ 3”
  • Width of rough opening= 12’3”
  • Height of door= 7’
  • Height added for rough opening= 1.5”
  • Height of rough opening = 7’+1.5”
  • Height of rough opening= 7’1.5”

Rough opening for 16’ garage door

This size is commonly used for two cars parking. For 16’ garage door the rough opening will be calculated by adding 3” to width of door which is 16’ wide and 1.5” will be added to height of door. The height of door varies from 7’ to 8’ depending upon the type of vehicle and suitability for garage.

Also Read: Glass sliding doors – components – Advantages & Disadvantages

Rough opening for 18’ garage door

This size is used for two cars parking. For 18’ garage door the rough opening will be calculated by adding 3” to width of door and 1.5” will be added to height of door. The height of door varies from 7’ to 8’ depending upon the type of vehicle and suitability for garage.

  • Width of door= 18’
  • Width added for rough opening= 3”
  • Width of rough opening= 18’+ 3”
  • Width of rough opening= 18’3”
  • Height of door= 7’
  • Height added for rough opening= 1.5”
  • Height of rough opening = 7’+1.5”
  • Height of rough opening= 7’1.5”
Door Size (width x height)Rough opening width (adding 3”)Rough opening height (adding 1.5”)
5×65’-3”6”-1 ½”
16×716’-3”7”-1 ½”
16×816’-3”8”-1 ½”
18×818’-3”8”-1 ½”
10×910’-3”9”-1 ½”
10×1010’-3”10”-1 ½”
8×78’-3”7”-1 ½”
9×7 9’-3”7”-1 ½”

Conclusion

Different countries use different size of garage doors according to the size of vehicles. The rough opening of garage door is larger than the size of door. For rough opening 3” is added to width of door and 1.5” to height of door. The rough opening of garage door is necessary for accurate installation of door in opening.

Saad Iqbal is a professional civil engineering and freelance write. He's passionate about structures, construction management, and home improvement topics. He's been working as a Senior Engineer in a consultant firm for over 8 years. Besides he loves writing informative and in-depth content focused on construction and home-related topics. You can catch him at his linkedin page or reach out via our contact us page.

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