Sizing and engineering · Rolling Shutter Guide
What is the smallest rolling shutter you can build?
It depends on how the shutter is operated. A strap or crank shutter can be as narrow as about 10 in overall. A motorized shutter needs at least 22 in of clear opening, and below 24 in only the smallest 10 Nm motor fits. A spring-loaded shutter needs at least 31 in overall.
Key facts
- Strap and crank shutters: about 10 in overall, limited by how small the axle inserts can go. Roll-A-Shield data
- Motorized shutters: 22 in of clear opening is the hard floor; from 22 in to just under 24 in clear only a 10 Nm motor is short enough. Roll-A-Shield data
- From about 24 in clear (about 28 in overall) any motor size can be fitted. Roll-A-Shield data
- Spring-loaded shutters: 31 in overall minimum. Roll-A-Shield data
- The minimum width is set by the operator, not by the slat. Roll-A-Shield data
Applies to: Roll-A-Shield rolling shutters with pull-strap, crank, spring-loaded, wired or radio tubular motors (Gaposa, Somfy) and OZRoll battery motors; small windows, counters, cabinets and pass-throughs.
Rolling shutters have no practical minimum set by the slat. The smallest size comes from the operator: how small the axle inserts can go on a strap or crank shutter, and how much room the spring or the tubular motor needs. So the first question for a small opening is how you want to operate it.
Smallest width by operator
| Operator | Smallest width | Measured on | Why |
|---|---|---|---|
| Pull strap or crank | about 10 in | overall | As small as the axle inserts allow |
| Motor, 10 Nm only | 22 in | clear opening | The 10 Nm motor is the only one short enough below 24 in clear |
| Motor, any size | 24 in (about 28 in overall) | clear opening | Larger motors are longer |
| Spring-loaded | 31 in | overall | The spring housing will not fit any narrower |
| OZRoll battery motor | not bound by the 22 in floor | — | See below |
"Clear opening" is the width of the hole being covered; "overall" includes the guide rail on each side. Rails run from 2.0875 in to 3.346 in per side, so overall is roughly 4 to 7 in more than clear.
How small can a motorized shutter be?
22 in of clear opening. Below that no tubular motor fits, and the factory system flags the shutter as too small for a motor. Between 22 in and just under 24 in clear, only the 10 Nm motor is short enough; it lifts a curtain of up to about 33 lb on a 60 mm axle, which is far more than a curtain that narrow weighs. From about 24 in clear, roughly 28 in overall, any motor size can be fitted, so the motor is chosen by the curtain's weight as usual. See What size motor does my rolling shutter need?.
OZRoll battery motors are not bound by the 22 in floor. OZRoll's own handbook gives about 300 mm (12 in) as the smallest shutter for its 10 Nm lateral (pancake) motor, which is made for shutters too narrow for a tubular motor. If you need a battery shutter narrower than 22 in, call to confirm it can be built.
How small can a manual shutter be?
A pull-strap or crank shutter is the smallest option, at about 10 in overall. The limit is how small the axle inserts can go. That makes strap and crank the only choice for very narrow openings: a 15-3/4 in opening, for example, is too narrow for a motor or a spring, so it would have to be a strap or crank shutter, and a build that small is confirmed with the factory before it is quoted.
A spring-loaded (push-up) shutter needs at least 31 in overall, because the spring housing will not fit any narrower. More on how they work is in Spring-loaded (push-up) shutters.
Do small shutters need a smaller box?
They use the smallest box their curtain allows. The box is picked mainly by curtain height, which is the clear opening height plus 2 in, not by width. The smallest Roll-A-Shield box is 6.5 in, and it holds a 38 mm insulated curtain up to 60 in, so a clear opening up to 58 in tall; the 55 mm insulated slat starts at the 8 in box. So a short counter or cabinet shutter on the 38 mm slat usually has a 6.5 in box, while a narrow but tall window needs a bigger one. Box sizes are in What size box do I need?, and counters in Counter pass-through and concession shutters.
What next
Measure the clear opening width and height, decide on strap, crank, spring or motor, and send them on a quote request, or call (480) 921-0200 for a size near one of these limits.
Frequently asked questions
Can a small window have a motorized shutter?
Yes, if the clear opening is at least 22 in wide. Between 22 and 24 in it must use the 10 Nm motor; from 24 in any motor size fits.
Why does a spring shutter need to be wider than a strap shutter?
The spring housing needs more room than a strap; below 31 in overall it does not fit.
Is there a minimum height?
No minimum height is published. Short shutters use the smallest box their slat allows: 6.5 in on the 38 mm insulated slat, which takes a curtain up to 60 in (a clear opening up to 58 in), and 8 in on the 55 mm insulated slat.
Is the motor minimum measured on the opening or the whole shutter?
On the clear opening: 22 in of opening, not counting the guide rails.
Parts and next step
Need a part or a hand?
Replacement motors, remotes, straps, slats and hardware ship from our Tempe, Arizona factory. Phoenix-area owners can book a service visit; everywhere else, our technicians help by phone. Call (480) 921-0200; the factory answers technical questions for any rolling shutter, not only ours.