How to Replace the Strap of a Roller Shutter (by Capitan Farloc)

Is the belt of your roller shutter worn out or completely broken? Don’t worry! Replacing the strap of a roller shutter may look like a professional’s job, but it’s actually a task that any DIY enthusiast can handle. In this step-by-step guide, we’ll show you how to do it safely and efficiently, using just a few common tools. With a little patience, your shutter will be back in perfect working order—no technician needed!

Replacing the Strap Before It Breaks

In this article, I’ll explain how to replace a roller shutter strap (in Italy known as a "tapparella" or "avvolgibile") in just a few simple steps.
The first thing to keep in mind is that the strap should be replaced before it breaks.
For safety reasons, it’s definitely better to replace the strap before it snaps, causing the shutter to suddenly crash down. This could not only harm someone but might even cause the shutter to come out of its guides or break some of its slats. When the strap is worn out, it typically looks like the one in the photo—frayed and significantly thinned at the edges.
In some cases, the remaining threads on the strap may even get stuck in the internal mechanism, making it difficult to raise and lower the shutter. If you notice any of these signs on your strap, then it’s definitely time to replace it.

Opening the Roller Shutter Housing

To begin the work, you’ll need to fully lower the shutter.
Once the shutter is down, you can open the access panel to the roller shutter housing.
If the panel is located at the bottom, I recommend carrying out this step with caution, as dust and debris often accumulate there. These could fall on your head or make a mess of whatever is beneath.
After removing the panel, you’ll have access to the housing, where the roller that the shutter wraps around is located. Attached to this roller, you can see the pulley, which the strap wraps around to raise and lower the shutter.

Removing the Strap’s Return Spring

Next, you’ll need to remove the plate that covers the winder—a spring-loaded mechanism that retracts the strap.
To do this, unscrew the two screws that hold it to the wall. However, before proceeding, it’s advisable to pull the strap slightly so that it stays loose and doesn’t pull on the piece while you’re dismantling it.

Unwinding the Winder’s Spring

Once the strap winder has been removed, you’ll need to proceed with caution. The winder looks like a metal drum with the remaining portion of the strap wrapped around it. Inside, there is a spring that retracts the strap as the shutter is raised, pulling the cord downward. To free the strap, firmly hold the drum and the bracket to which it is attached with one hand to prevent the spring from causing it to spin. When you are certain that everything is secured, release the strap from the locking mechanism, which might use a tab (as shown in the photo) or a screw. With the strap removed, slowly rotate the drum while continuing to hold the frame with one hand and the drum with the other to prevent the cylinder from suddenly spinning and releasing the spring all at once. While rotating the drum, count the number of turns it makes until the spring is fully unwound—usually between 10 and 15 turns. This count is crucial because when you install the new strap, you’ll need to rewind the spring with the same number of turns.

Removing the Old Strap

After freeing the strap from the bottom, pull it through from the inside of the upper housing to remove it from the pass-through hole where it enters the wall. Mounted on this hole is the strap guide, a system with two metal or plastic rollers designed to reduce friction during the transition from outside to inside the wall. Check if the lower roller is worn; if it is, it should be replaced because a worn or broken roller will quickly wear down the new strap as well. If you’re unable to purchase a new roller set, you can temporarily "make do" by disassembling it and reinstalling it upside down so the upper roller (if still intact) ends up at the bottom. However, I recommend replacing it as soon as possible.

Removing the Old Strap from the Pulley

At this point, remove the old strap from the pulley one turn at a time (counting the turns this time as well) until the strap is completely detached from the pulley. Finally, the strap will be inserted into a slot in the pulley and secured with a knot. If the knot is too difficult to untie, you can simply cut it with scissors. Once the old strap is removed, use it as a reference to measure the new strap and cut it to the correct length.

Winding the New Strap onto the Pulley

To install the new strap, you’ll need to reverse the steps taken during its removal. First, insert the end of the strap into the designated slot on the pulley, leaving about 10cm of excess to tie a securing knot. Then, by pulling on the strap, take up the slack, ensuring the knot locks into the slot’s opening. Next, wind the strap around the pulley, completing the same number of turns as counted when removing the old strap. Be mindful during this process, as the inside of the roller shutter housing is naturally dusty, and the new strap could easily become dirty. Before proceeding, it’s a good idea to clean the area with a vacuum cleaner and do your best to avoid letting the strap come into contact with dirty surfaces.

Reinstalling the Strap onto the Winder Drum

After winding the new strap onto the internal pulley, guide it outside by passing it through the strap guide with the rollers. Next, wrap the strap around the winder drum. However, before doing so, remember to insert the brass or plastic plate that serves as a decorative cover for the winder assembly. Once the strap is reassembled, it will no longer be possible to install this plate. Pay particular attention to the winder’s entry hole for the strap, which is equipped with a locking mechanism when the strap is in the resting position. The correct way to thread the strap through this locking mechanism is shown in the photo. If this step is not followed correctly, the locking system won’t function, and the shutter may occasionally start to lower on its own (especially when it’s nearly fully lowered).

Reassembling the Winder Drum

After completing the necessary steps (as shown in the photo, where the strap is correctly threaded through the brass plate and winder), proceed to wind the spring. Using the same caution as before (if the drum slips while the spring is loaded, it can cause serious injury), rotate the drum to wind the spring the exact number of turns counted previously. Next, attach the new strap and resecure the winder and plate to the wall using its screws. With this done, the task is complete. Carry out a quick test to ensure everything is working correctly.

I Hope This Article Was Useful

Thank you!
Luciano (Capitan Farloc)