Key facts

• You need at least 3 times the height of the window or door in strap; Roll-A-Shield sells white flat nylon strap in 15, 20, 25 and 30 ft lengths. Roll-A-Shield data
• Roll-A-Shield's strap shutters use a 15 mm flat strap, and those 15 mm strap manual shutters carry a 1-year warranty. Roll-A-Shield data
• The strap must hang straight from the diamond roller into the box; a strap that runs at an angle wears out early. Roll-A-Shield data
• Cut the strap about 1 ft below a pull-strap box, or about 3 ft below a crank box, then slit it about 1 in from the end. Roll-A-Shield data
• Do not open a crank box; the strap is clamped under a metal band at the top of the box. Roll-A-Shield data
• Roll-A-Shield's service-desk guide puts broken straps at about 40% of service calls. Roll-A-Shield data

Applies to: Pull-strap and crank-box rolling shutters that use a flat strap through the wall, including Roll-A-Shield's.

A broken strap is one of the most common rolling-shutter repairs: Roll-A-Shield's service-desk guide puts broken straps at about 40% of service calls. When the strap is not broken, the usual problem on a crank shutter is the handle being turned the wrong way; check that first on Why won't my rolling shutter go up or down?. If the strap is frayed, snapped, or the shutter slammed down when it let go, this page is the fix.

Following this Roll-A-Shield guide does not void your warranty; mains wiring must be done by a licensed electrician. Roll-A-Shield's 15 mm strap manual shutters carry a 1-year warranty.

How much strap do I need, and what width?

Buy at least three times the height of the opening. The strap runs from the strap disc on the axle, down the back of the shutter, through the wall, down to the box, and some of it is always wound on the disc or the drum, so a 7 ft door needs at least 21 ft of strap. Roll-A-Shield sells white flat nylon strap in 15, 20, 25 and 30 ft lengths in the parts store.

Roll-A-Shield's strap shutters use a 15 mm flat strap, just under 5/8 in wide. On another maker's shutter, measure the old strap's width before you order; the strap has to pass through the slot in the diamond roller and under the flap of the box.

What tools do I need?

• Replacement strap, at least 3x the opening height
• Phillips and flathead screwdrivers
• Scissors or a utility knife
• A ladder to reach the shutter box, and a helper inside while you pass the strap through the wall

You do not need to take the shutter off the wall, but you do open the shutter box to reach the strap disc. If the diamond roller or strap box is also worn (the roller and the pull-strap box are two of the most-reordered wear parts), replace them at the same time.

How do I replace the strap on a pull-strap box?

1. Lower the shutter fully so the strap is slack and the roll cannot drop.
2. Pry open the front of the box, unwrap the strap from the spring drum and unhook it from the strap lug.
3. Turn the drum counter-clockwise until the locking tab shows, then pull the tab back with a screwdriver so the locking arm holds the drum. The drum is now safe to leave.

4. Pull the old strap up out of the box and the diamond roller, then back out through the wall from the shutter side.
5. Inside the shutter box, the strap's other end is fixed to the strap disc on the axle. To reach it, take off the box's bottom front cover. If the hanging straps that hold the curtain to the axle are in the way, unhook them (they are held by screws or pop rivets; rivets are drilled out) and slide the safety plate aside; the hanging straps go back on with screws.
6. Fasten the new strap end to the strap disc with a screw, flat and untwisted, then fill the disc by turning the axle away from you.

7. Feed the new strap through the 3/4 in hole in the wall, flat and untwisted, while your helper pulls slowly from inside.
8. Thread the strap through the slot at the back of the diamond roller so it falls straight over the roller.
9. Cut the strap so about 1 ft hangs below the box. Fold the end and cut a small vertical slit about 1 in from the end.
10. Lift the small metal flap at the top of the box, feed the strap under it, wrap it around the spring drum and slide the slit over the strap lug. Tug it twice to confirm it is on.
11. With both hands, pull the strap to turn the drum counter-clockwise until the locking tab lifts, keep one hand on the strap behind the lug, and press the tab into the opening behind it with a screwdriver to release the spring. Let the drum coil the slack slowly.
12. Close the box. Pull straight down to raise the shutter; pull toward your waist to lower it.

How do I replace the strap on a crank box?

1. Lower the shutter fully.
2. Crank until the strap end reaches the box, then tug the strap up to expose the metal band. Straighten the band and slide the old strap off.
3. Remove the old strap through the roller and the wall, fix the new strap at the strap disc as in the pull-strap steps above, and feed it back through the wall and the diamond roller.
4. Cut the strap so about 3 ft hangs below the box, and cut a 1/2 in vertical slit about 1 in from the end.
5. Slide the slit onto the straightened metal band, rotate the strap 90 degrees so it lies parallel to the band, and fold the band down over the strap.
6. Fit the crank handle in the square opening at the bottom right of the box and turn it slowly clockwise, guiding the band past the entrance rollers. Clockwise raises, counter-clockwise lowers.

Why does the strap need to hang straight?

The box must sit directly below the diamond roller, at about waist height, so the strap drops straight into it. A strap that enters the box at an angle wears out early. If your box is off to one side, move it when you fit the new strap: a pull-strap box takes two fasteners, a crank box four.

What if the strap won't coil back into the box?

If the slack will not coil into a pull-strap box, check that the locking tab was released in step 10. If it was and the drum still does not take up the strap, call; the box may need replacing. A pull-strap box replacement is the same job with the box swapped at step 3; a crank-box swap is shown in the Roll-A-Shield service video.

What next

Strap, diamond rollers and crank handles are in the Roll-A-Shield parts store; for a replacement pull-strap box or crank box, check the store or call (480) 921-0200. In metro Phoenix, Roll-A-Shield's service team services rolling shutters of any make.

Watch it done

Service tutorial: pull-strap box replacement

The written steps on this page are the reference; the video shows the same job.

Frequently asked questions

How much strap do I need?

At least three times the height of the opening. Measure the height of the window or door, multiply by three and round up to the next length sold.

What width is the strap?

Roll-A-Shield's strap shutters use a 15 mm (just under 5/8 in) flat strap. On another make, measure your old strap before ordering.

Why does my strap keep breaking?

A common cause is a strap that runs at an angle from the diamond roller into the box. Roll-A-Shield's install manual mounts the box directly below the roller at about waist height so the strap drops straight in, because an angled strap wears out early.

Can I replace my pull strap with a crank?

A crank box mounts in the same place, directly below the diamond roller, with four fasteners. It needs about 3 ft of strap below the box instead of about 1 ft, so plan on new strap. Call (480) 921-0200 to confirm it suits your shutter.

Related questions

• Why won’t my rolling shutter go up or down?
• What are the parts of a rolling shutter?
• Can I install a rolling shutter myself?
• How do I install a strap or crank rolling shutter?
• Shop rolling shutter parts
• Rolling shutter repair in metro Phoenix