Sizing and engineering · Rolling Shutter Guide
How big can a manual rolling shutter be before it needs a motor?
Strap and crank shutters stop at a curtain weight of about 50 lb, roughly 56 sq ft of 38 mm insulated slat; a pull strap reaches 24 sq ft and 120 in wide. Spring-loaded shutters go further, to 192 in wide, 120 in of curtain height and 144 sq ft. Anything larger, and every 55 mm insulated shutter, is motorized.
Key facts
- Pull strap, crank strap and crank wand shutters share a curtain-weight cap of about 50 lb. Roll-A-Shield data
- A pull strap is limited to 24 sq ft of curtain and 120 in of width; a crank strap to 64 sq ft. Roll-A-Shield data
- Spring-loaded shutters are limited to 192 in wide, 120 in of curtain height, 144 sq ft and a box of 10 in or smaller. Roll-A-Shield data
- The 55 mm insulated slat is built motorized only. Roll-A-Shield data
- Curtain weight = width x height x the slat's sizing weight per sq ft / 144, with the height taken as the opening plus about 2 in. Roll-A-Shield data
Applies to: Roll-A-Shield pull-strap, crank-strap, crank-wand and spring-loaded rolling shutters on 38 mm insulated and 63 mm single-wall slats; the same weight logic applies to most makes.
The limit on a manual shutter is weight, not width. A strap or a crank has to lift the whole curtain by hand, so once the curtain passes a certain weight a strap or crank is not offered, however the width and height are split. Width and height still matter, because they set the weight, and some operators also have size limits of their own.
What are the limits for each manual operator?
| Operator | Curtain weight | Size limits |
|---|---|---|
| Pull strap | about 50 lb | up to 24 sq ft and 120 in wide |
| Crank strap (crank box on a strap) | about 50 lb | up to 64 sq ft |
| Crank wand (geared crank) | about 50 lb | larger areas allowed, but the weight cap still applies |
| Spring-loaded (push-up) | sized to the curtain | up to 192 in wide, 120 in of curtain height, 144 sq ft, box 10 in or smaller |
| Motor | by motor size | up to the slat's own limits |
The strap and crank weight cap is 52 lb in Roll-A-Shield's sizing, about 50 lb in round numbers. The areas, the weights and the spring's height limit are all for the curtain: the opening width times the opening height plus 2 in. So the spring's 120 in curtain height is a clear opening up to 118 in.
The 55 mm insulated slat is not offered on any manual operator; it is built motorized only.
How big is the manual weight limit in real openings?
On the 38 mm insulated slat, at a sizing weight of 0.92 lb per sq ft, about 56 sq ft of curtain. On the heavier 63 mm single-wall slat, at 1.14 lb per sq ft, about 45 sq ft. Some 38 mm examples:
| Opening (W x H) | Curtain area | Curtain weight | Manual options |
|---|---|---|---|
| 36 x 48 in window | about 12.5 sq ft | about 12 lb | pull strap, crank, spring |
| 48 x 60 in window | about 21 sq ft | about 19 lb | pull strap, crank, spring |
| 72 x 84 in door | about 43 sq ft | about 40 lb | crank strap or crank wand, spring |
| 96 x 96 in opening | about 65 sq ft | about 60 lb | spring, if a spring suits it; otherwise motor |
| 144 x 96 in (12 x 8 ft) | about 98 sq ft | about 90 lb | spring, if a spring suits it; otherwise motor |
The weights use the sizing figure, which carries a safety margin over the slat's actual weight, so a scale would read a little less. Work out your own with the table in How much does a rolling shutter weigh?.
How big can a spring-loaded shutter be?
Up to 192 in (16 ft) wide, 120 in (10 ft) of curtain height and 144 sq ft, in a box no bigger than 10 in; all of these limits apply together, so a shutter cannot be at full width and full height at once. A spring-loaded shutter is raised and lowered by hand with no strap or crank, and its spring and axle are chosen from the curtain's height and weight when it is built; if no spring suits that height and weight, it is not offered. Spring units are offered on the 63 mm single-wall slat as well as the 38 mm. The smallest spring shutter is 31 in wide overall. How they work is in Spring-loaded (push-up) shutters.
Even within the limits, when is a motor the better choice?
On tall shutters and on heavy ones. Raising a very tall shutter by crank takes a long time, and in practice large openings go motorized even where a manual operator is technically allowed. The limits above are what the factory can build; Roll-A-Shield's own recommendation is a motor once an opening is over about 12 ft wide or the curtain is over about 100 lb. Above the manual limits the factory sizes a motor to the curtain weight instead. If you want hand operation as a backup, choose a motor with a manual override, which can be cranked when the power is off; see Manual override.
Roll-A-Shield does not build manual shutters ready for a motor to be added later; converting one is done as a service. See Converting a manual shutter to motorized.
Can I split one big opening into two manual shutters?
Yes, if each half fits the manual limits on its own and there is a solid post or mullion between them for the two inner guide rails; every shutter is built as its own unit. A 13 ft opening, for example, could become two shutters of about 6-1/2 ft, each light enough for a crank at window heights. See Covering a very wide opening.
What next
Send each opening's clear width and height on a quote request, or call (480) 921-0200, and the factory will confirm which operators fit. Budget figures for manual and motorized shutters are in How much do rolling shutters cost?.
Frequently asked questions
Can I have a twelve-foot-wide manual shutter?
As a strap or crank shutter, rarely: at 12 ft wide the curtain passes about 50 lb at a height of under 5 ft on the 38 mm slat. As a spring-loaded shutter, the factory can build it up to 144 sq ft and 120 in of curtain height, though from around that width Roll-A-Shield recommends a motor.
Can I split one big opening into two manual shutters instead of one motorized one?
Yes, if each half stays inside the manual limits, and there is a solid post or mullion for the two inner guide rails.
Can I buy it manual now and add a motor later?
Roll-A-Shield does not sell motor-ready manual shutters. Converting a manual shutter to a motor later is done as a service.
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.