Understanding Rough Openings for Doors
When it comes to installing iron doors, one of the key terms you'll encounter is "rough opening." Understanding rough openings is essential for anyone looking to install any door, whether it's a in-stock prehung interior door or a custom built exterior door. This guide will break down what rough openings are, why they matter, and how to calculate them for various door sizes. Let's dive in.

A rough opening refers to the framed opening in a wall where a door will be installed. It includes the space for the door itself, as well as additional room for the door frame, any necessary shims, and insulation. The rough opening is crucial because it ensures that your door fits perfectly and functions properly.
Importance of Accurate Rough Openings
An accurate rough opening is vital because it impacts the ease of installation and the door's performance. If the rough opening is too small, the door won't fit. If it's too large, you might end up with gaps that could lead to drafts or a door that doesn't hang correctly. Thus, understanding and measuring rough openings correctly can save you time and frustration during the installation process.
How to Measure a Rough Opening
Measuring a rough opening requires careful attention to detail. Here's a step-by-step guide:
Tools Youāll Need
- Measuring tape
- Pencil and paper
- Level
Steps to Measure
- Width Measurement: Measure the width of the opening from one stud to the other. This measurement determines the rough width.
- Height Measurement: Measure from the floor to the bottom of the header. This is your rough height.
- Depth Measurement: Measure the thickness of the wall where the door will be installed. This is often the thickness of the studs plus any drywall or paneling.
Standard Rough Opening Sizes

Hereās a general guide to standard rough opening sizes for various door dimensions:
- 6080 Door: Rough opening should be 73 inches wide by 96.5 inches tall.
- 3080 Door: Rough opening should be 37 inches wide by 96.5 inches tall.
- 3069 Door: Rough opening should be 37 inches wide by 81.5 inches tall.
- 36 x 80 inch Door: Rough opening should be 37 inches wide by 80.5 inches tall.
- 48 x 96 inch Door: Rough opening should be 49 inches wide by 96.5 inches tall.
- 72 x 96 inch Door: Rough opening should be 73 inches wide by 96.5 inches tall.
These measurements account for a half-inch gap on each side for shimming and adjustments.
Understanding Prehung Door Rough Openings
A prehung door comes with its own jamb, which makes installation easier as it fits into the rough opening as a single unit. However, it still requires precise rough opening measurements.
Prehung Interior Door Considerations
For prehung interior doors, add an extra .50 inches to the doorās width and .25 inches to the height. This allows room for the door jamb and a perfect fit.
Example for a 32-Inch Prehung Door
For a 32 x 81 inch prehung interior door:
- Rough Width: 32.25 inches
- Rough Height: 81.25 inches
Rough Openings for Double Doors

Double doors require a wider rough opening than interior doors. To calculate this, add 1" the width and add .5" to the height.
Example for Double 72x 96 Inch Doors
For two 72 x 96 inch doors:
- Rough Width: 73 inches (72"+ 1")
- Rough Height: 96.5 inches (96" + .5")
Troubleshooting Common Rough Opening Issues
Uneven Openings
If your opening is uneven, it can lead to installation challenges. Use a level to check for plumb and make adjustments to ensure the frame sits squarely.
Adjusting for Non-Standard Sizes
If your door size doesnāt fit standard dimensions, you might need to adjust the studs or use a custom door. Consult with a professional if you encounter this scenario to ensure a proper fit.
FAQs About Rough Openings
What Is the Rough Opening for a 3080 Door?
A 3080 door, which refers to a 36-inch x 96-inch door, requires a rough opening of 37 inches wide by 96.5 inches.
What Is a 6080 Rough Opening Used For?
A 6080 rough opening is typically used for 72x96" double doors, allowing ample space for installation and operation.
Why Is the Rough Opening Larger Than the Door?
The rough opening is larger to accommodate the door frame, any necessary shims for leveling, and to allow for adjustments during installation.
Conclusion
Understanding rough openings is a fundamental aspect of door installation. Whether you're dealing with a standard door size or a custom setup, knowing how to measure and adjust your rough opening ensures a smooth installation process. With this guide, you're equipped to tackle any door project with confidence.
Remember, precise measurements and planning are key to a successful door installation. Happy building! Reach out if you need assistance.

