Roller shutter strap snapped – replace it yourself
Difficulty: Medium · Time: approx. 45 minutes
One firm pull and suddenly you're holding the end of the strap: a snapped roller shutter strap is one of the most common shutter failures of all. Over the years the webbing chafes against the guide and the winder until it finally gives way.
Replacing it is very doable if you work methodically – the only part that deserves respect is the pre-tensioned spring inside the winder. Allow about 45 minutes, and ideally read through all the steps once before you start.
What you'll need
- New shutter strap of the same width (usually 23 mm, mini 14 mm)
- Phillips screwdriver
- Scissors to cut the strap to length
- Lighter to briefly seal the cut edge
- Tape measure to check the strap width
- Optional: torch to see inside the shutter box
Step by step
- 1
Lower the shutter completely
First let the shutter all the way down – by hand if necessary, guiding it down carefully. This way the spring in the winder holds the least tension and the shaft at the top can't move unexpectedly. This step is mandatory before you unscrew anything.
- 2
Remove the winder and secure the spring
Unscrew the winder's cover plate and carefully pull the winder out of the wall. Careful: there's a pre-tensioned spring inside. Hold the winder firmly and let the spring unwind in a controlled way – counting the turns as you go. You'll need that number later for re-tensioning.
- 3
Detach the old strap
Pull the old piece of strap out of the winder. Then open the inspection flap or the lid of the shutter box at the top and detach the other end of the strap from the shaft – it's usually hooked in or screwed on there.
- 4
Attach the new strap to the shaft
Measure the width of the old strap – usually 23 mm standard, 14 mm on mini systems – and attach the new strap to the shaft first, exactly the way the old one was fitted. Then lay one or two wraps around the shaft in the same direction.
- 5
Thread the strap through
Guide the strap down through the strap guide in the window reveal – the same route the old one took. If you briefly seal the cut edge with a lighter first, it won't fray and will slide through the guide much more easily.
- 6
Hook it in and re-tension the spring
Hook the lower end of the strap into the winder. Now pre-tension the spring: exactly as many turns as you counted during removal. Push the winder back into the wall and screw the cover plate on.
- 7
Do a test run
Run the shutter all the way up and down once. The strap should wind up neatly and stay taut without sagging. If it hangs slack, take the winder out again and give the spring one or two extra turns of pre-tension.
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Upload a photo →Frequently asked questions
- Which strap width do I need?
- Just measure the old strap: the standard is usually 23 mm, small mini winders take 14 mm. If in doubt, take a piece of the old strap to the hardware store – and buy the length generously, it gets trimmed at the end anyway.
- Why does the shutter have to be fully down first?
- With the shutter up, the spring in the winder holds its full tension and the shaft could start unwinding uncontrollably when you detach the strap. Fully lowered, the system is largely relaxed – that's the only safe way to work.
- The new strap doesn't wind up neatly – what's wrong?
- Usually the spring lacks a bit of pre-tension: take the winder out again and give it one or two extra turns. Also check that the strap runs around the shaft in the same direction as the old one – fitted the wrong way round, it will never wind up neatly.