Your Ultimate Guide to Rollup Door Sizing
You wouldn't buy a custom piece of furniture without measuring your space twice. The same care should go into your new commercial rollup door. It's a significant investment, and getting the right rollup door dimensions for your is the first and most important step.
An incorrect overhead door measurement can lead to unwelcome surprises on installation day, causing frustrating delays and unexpected costs. But the good news is, you don’t have to navigate this on your own. Most projects of this scale have a team in place. An expert garage door dealer can manage the process from start to finish, and you’ll likely work with an architect or contractor who will keep your project on track.
Our guide makes it simple, walking you through easy steps to measure your door frame and our sizing option. You’ll have all the tools you need to confidently choose a door that suits your business, your budget, and your vision.
Key Takeaways
- • Measure three times, order once. Accuracy is everything. The success of your installation hinges on precise measurements of your rough opening, side clearance, and headroom.
- • Match the door to the job. Don't just pick a door that fits; pick one that performs. Use our chart to match your specific needs to the right model, and find some of our common sizes and clearance requirements.
- • When in doubt, ask the experts. Our guide empowers you to make a smart choice, but you don't have to do it alone. For non-standard openings or complex requirements, your local commercial door dealer is your most valuable resource.
Why It’s Important to Get the Right-Size Door
A commercial rolling door is both a piece of complex machinery and an architectural feature. Consequently, its installation requires professional expertise from planning and preparation to final setup.
If the size is wrong, or if it’s installed improperly, it’s only a matter of time before you run into some issues, including:
What Sizes Are Available for Rollup Doors?
Rollup doors serve a wide range of commercial purposes, from small counter shutters to massive doors, like the ones installed at this aerospace manufacturing facility. While there are some standard sizes, most coiling doors are customized to meet the unique needs of your building.
Cornell rollup doors are manufactured in a range of standard and custom dimensions. There are even custom solutions for unconventional spaces, such as slanted bottom bars for sloped terrains. The door curtain is made of interconnected slats (typically 2 5/8 inches high), and we can manufacture our door heights to a precise 1/16-inch increment.
How to Measure Your Space in 3 Simple Steps
This section explains exactly how to measure for a rollup door. You’ll need to take three key measurements. Grab a tape measure and let’s get started!
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Measure the Finished Door Opening
Begin by measuring the exact height and width of the finished doorway. This measurement is known as the rough opening. Measure the width and the height of the clear, finished opening where the door will go. Provide the exact measurement in feet and inches down to the 1/16", and do not round your numbers.
Pro Tip: If you’re replacing a rollup door in an existing building, check for any irregularities. Is the floor sloped? Are the side jambs perfectly vertical? If you notice anything out of the ordinary, make a note of it to discuss with our design team.
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Check Your Side Clearance
Side clearance is the empty wall space required on either side of the doorway. This area needs to accommodate the vertical door tracks (guides), the motor (operator), and other essential hardware.
To measure your clearance, take a horizontal measurement from the edge of each door jamb to the nearest obstruction, such as a wall corner, pipe, or column. The amount of space needed will vary depending on the door's size and model—typically ranging from 5 to 14 ¾ inches—as larger doors require larger operators. This measurement is an important factor in determining which motor and mounting options will work for your space.
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Determine Your Headroom
Headroom is the clear space above the door opening where the door coils up into a roll when it's open. Measure the distance from the top of the door opening to the lowest obstruction on the ceiling (like rafters, lights, or ductwork). The taller the door, the larger the coil, and the more headroom you will need. Depending on the door's size and model, the required headroom can range from 10 ½ to 31 inches.
Commercial partners, architects, and designers: Request color finishes to coordinate with your project submittals!
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Headroom Requirements by Door Model
Once you have your headroom measurement, you can compare it to the requirements of the door you're interested in. The table below provides a complete overview to help you compare our most popular models, from their intended use to their size and space requirements.
| Door Model | Best For... | Common Size Range | Required Headroom (Clearance) |
|---|---|---|---|
| Rollup Service Door | General-purpose interior and exterior use. | Up to 30' W x 30' H | 14" to 24" |
| StoreDefender™ Door | Retail and storefront riot protection. | From 2'4" x 3' up to 30' x 40' | 14" to 25" |
| Extreme® 300 Series Door | High-traffic areas needing speed and durability. | Up to 30' W x 20' H | 15" to 25" |
| Extreme® 1024 Series Door | Long-life durability in high-cycle areas. | Up to 30' W or 20' H | 19" to 29" |
| StormDefender® | Areas needing protection from hurricanes and high winds. | From 3' x 3' up to 14' W x 16' H | 19" to 29" |
| EntryDefender® | Government and high-security facilities. | Up to approx. 14' W x 16' H | 19" to 29" |
| Thermiser Max® – Low U, Thermiser Max® and Thermiser® | Maximum energy efficiency and climate control | Up to 30' W x 30' H | 17" to 31" |
| Rolling Fire Door (Standard) | Mitigating the spread of fire and smoke and meeting fire code requirements. | From 4' x 4' up to 13'6" x 12' | 14" to 16" |
Your Final Pre-Installation Checklist
You’ve taken your measurements and reviewed the door specs. Before you finalize your decision, do one last walkthrough of your space to confirm these four key details. This will help ensure a smooth installation and flawless operation for years to come.
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Is the structure sound?
Your door framing must be in good condition. Confirm that the header is level, the jambs are plumb (perfectly vertical), and the entire structure is solid enough to support the full weight of a heavy commercial door.
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Where is the power source?
Unless you are planning for a manual push-up or a chain-operated door, you'll need power for the motor. Locate the nearest electrical outlet and note if it is on the left or right side of the opening, as this can influence your choice of a left- or right-hand motor.
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Where will the controller be mounted?
The door controller needs a permanent spot on the wall. Decide where you want it placed, ensuring you have enough space. This is especially important for advanced models like our Direct Drive and APEX Pro SmartController™, which has a larger LCD screen than a standard push-button remote.
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Do a final check for obstructions.
You already measured your side room and headroom by noting the nearest obstructions. Now, do one last visual sweep. Confirm that no new pipes, conduit, or other fixtures have been installed in that reserved space since you first measured.
Frequently Asked Questions (FAQ)
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What if my opening isn't a perfect square or has a sloped floor?
This is a common challenge, especially in older buildings or on graded tarmacs. We can create custom solutions, like slanted bottom bars, to ensure a perfect seal on uneven surfaces. It's important to note these irregularities and discuss them with our team.
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How do I know if I have enough structural support for a heavy door?
If you have any doubts about the strength of your header or wall framing, we strongly recommend consulting a structural engineer or a general contractor before proceeding. They can assess the load-bearing capacity and recommend any necessary reinforcements.
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What's the main difference between a high-performance door and a standard service door?
A standard service door is a durable workhorse designed for reliability in typical-use conditions (a few cycles per day). A high-performance door, like our Extreme® Series, is engineered for facilities with constant traffic (hundreds of cycles per day). They are built for extreme speed, durability, and a much longer lifespan with less maintenance.
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Can I just use the door opening measurements and have you figure out the rest?
While the rough opening is the starting point, the side room and headroom measurements are just as important. Those dimensions determine which motor, track, and mounting hardware configurations are physically possible for your space. Providing all three measurements ensures we can specify a door that will fit and function.
Ready to Find Your Perfect Fit?
Now that you know how to measure your space and have an idea of the models available, you’re ready to make an informed decision. Having these measurements on hand will make the specification process smooth and efficient.
Need help specifying your door, or ready to discuss a custom solution?
