Blocked roller shutter: diagnosis and fixes, part by part

Seven hundred cycles a year per window: when a roller shutter blocks, it rarely does it halfway. Before calling — or worse, forcing — here is the part-by-part diagnosis. Rule number one: never force. A derailed slat bends, a motor in stall burns, a tired attachment drops the curtain into the box.

Failure 1: the strap (manual shutters)

Frayed then parted, or winding in the void: the number-one failure, a wear part lasting 10–15 years. Fix: strap and winder check, €90–160, half an hour. DIY is feasible on an accessible box for a good handyman — unreasonable on an outdoor box upstairs.

Failure 2: curtain off its guides

Shutter descending crooked, slats overlapping or gaping: wind on a half-closed shutter, a brutal manoeuvre, an obstacle on the sill. Fix: re-tracking, slats replaced singly, attachments checked — €120–300. Every extra cycle bends more slats: stop manoeuvring and book the repair.

Failure 3: the motor

Hums but nothing moves: transmission failed — repairable by the part on many models. Runs then cuts out: thermal protection — often end of life, or overload from a dragging curtain. Silent: check the breaker and the remote's battery first — the €3 "repair" we diagnose weekly by phone. Motor replacement: €250–550, the natural moment for radio control and presence-simulation timers.

Failure 4: inside the box

A dull clap then a very heavy curtain (compensation spring), a curtain fallen into the box (attachments), metallic grinding (bearings). Box work under mechanical tension: this is where DIY stops. €90–300 by the part.

Failure 5: frost and seasons

A shutter refusing to rise on a freezing morning may just be frozen to the sill — forcing tears slats; wait for thaw or pour lukewarm water. Sticky shutters in damp weather often mean clogged guides: clean and dry-lubricate (never grease). Spring guide-cleaning and an autumn listen to a full cycle prevent most winter calls — and a semi-annual quarter-hour of maintenance is the difference between shutters lasting twenty-five years and shutters collecting emergencies.

Symptom → cause → price

When failures chain on a 20-year-old shutter, the one-third rule applies: past a third of a new shutter fitted (from €400), we quote both — and replacement brings motorisation and anti-lift security into the conversation. A shutter blocked closed on a living room is an emergency, weekends included.