Mechanical shutters (called persianas locally) rely on a continuous fabric or nylon cord looped through a drum mechanism at the top. The drum is held under tension by a spring. When you pull the cord down, your weight winds the shutter onto the drum. When you release it, the spring rewinds the cord and raises the shutter.
The cord has lost tension. After years of use, the spring in the drum weakens or the cord stretches slightly. The shutter descends because gravity does most of the work, but the spring no longer has enough force to pull the shutter up against the weight of the slats.
The cord is twisted or looped inside the housing. This is the most common culprit, especially in holiday homes or properties that aren't used regularly. Dust, debris, or a slight misalignment causes the cord to twist back on itself where it enters the drum. The shutter can still descend (because you're pulling), but the twisted section blocks the return path.
Paint or debris has accumulated in the housing. Coastal properties in particular suffer from salt spray and dust buildup. Over time, this clogs the cord track or the drum spindle, creating friction that the weakened spring cannot overcome.
The cord has partially frayed or snagged. If previous owners pulled too hard or the cord rubbed against a sharp edge inside the housing, internal strands fray. A frayed section can catch on the drum or the housing edge, jamming the mechanism.
The drum spring has failed entirely. This is less common but possible after 15–20 years of daily use. The spring loses all elasticity and cannot rewind the cord at all. In this case, the shutter will descend freely but won't return no matter how hard you pull.
If the shutter moved slightly during your gentle pull, the spring is weak but functional. You can temporarily improve its performance:
- Pull the cord down very slowly until the shutter is fully open.
- At the top, where the cord enters the housing, you'll sometimes see a small knot or loop. If the cord has stretched, this loop may have slackened. Do not untie it or attempt to adjust it yourself — this voids safety and can snap the cord — but you've identified the likely cause.
- From now on, avoid letting the shutter slam down. Lower it by hand, holding the cord, rather than releasing it suddenly. This reduces shock to the mechanism.
If you spotted dust or paint flakes near the cord entry point:
- Use a dry brush or old toothbrush to gently sweep away surface debris from the housing opening.
- Do not spray water or use compressed air into the housing; this can push debris deeper into the mechanism.
- Do not attempt to disassemble any part of the housing.
If the shutter is stuck halfway and you need to keep it closed temporarily (for privacy or security):
- Close it as far as it will go using gentle, steady pressure.
- Insert a wooden baton, broom handle, or sturdy stick horizontally through the shutter slats on the interior side, resting both ends on the window sill or frame. This prevents it from falling further if the cord slips.
- This is a temporary measure only — do not rely on it for more than a day or two.
Stop and call a professional handyman immediately if any of these apply:
- The cord is visibly frayed, torn, or discoloured. A damaged cord can snap without warning, and the shutter will fall. This is a safety hazard.
- You hear a grinding or crunching sound when you pull. This indicates internal damage to the drum or a slat jamming against the housing.
- The cord does not move at all, even with steady, gentle pulling. The mechanism is locked, likely from a snapped internal cord or a jammed drum. Forcing it will cause further damage.
- The shutter is stuck in a half-open position and the cord is completely slack. The cord may have snapped inside the housing.
- The housing is visibly cracked or the shutter is sitting unevenly in its tracks. This suggests structural damage that requires professional assessment.
- You live in a listed building or the shutter is motorised. Motorised systems have electrical components and require a specialist. For listed buildings, check with your local authority before repairs.
In any of these cases, do not pull the cord again. Contact a professional handyman who has experience with mechanical shutters.
A qualified handyman will arrive with basic tools: a ladder, cord tensioner or replacement cord stock, and possibly replacement drum or spring components.
They'll inspect the mechanism. They'll open the housing access panel (or remove the shutter if it's a removable unit) to see the drum, spring, and cord path directly. This takes 5–10 minutes and immediately reveals whether the spring is weak, the cord is frayed, or debris is jamming the mechanism.
They'll address the specific cause. If the spring has weakened, they'll tighten the spring tension using a hand tool (a process called "re-tensioning"). If the cord is frayed or stretched, they'll replace it with new nylon cord of the correct diameter and re-loop it through the drum. If debris or paint has clogged the housing, they'll clean it out carefully and may lubricate the mechanism with a light silicone spray (not WD-40, which attracts dust on shutters).
They'll test the shutter multiple times — raising and lowering it 5–10 times to confirm smooth operation and even tension.
They'll hand you a brief report. A professional will note what was done (e.g. "cord replaced", "spring re-tensioned") and whether any parts have been renewed. Keep this documentation; it's useful if the problem recurs quickly or if you sell the property.
Most repairs take 30–60 minutes. Costs typically range from €80 to €250 depending on whether it's a simple re-tensioning (€80–120) or a full cord or spring replacement (€180–250).
Pull gently. Mechanical shutters are not designed for sudden, jerky movements. Lower them by hand, controlling the descent with the cord, rather than releasing it suddenly. Over time, rough handling weakens the spring.
Don't leave them fully closed for months. Holiday homes are especially vulnerable. When a shutter stays closed for a long period, dust accumulates in the housing and the cord stiffens. If you're away, open the shutters weekly via a neighbour, or at minimum, cycle them (open and close) once a month.
Inspect twice a year. In spring and autumn, take 10 minutes to check the cord for fraying, the housing for visible debris, and listen for any grinding sounds when you open and close. Early detection prevents sudden failure.
Clean the housing annually. Use a soft brush to sweep out dust and debris from the top of the housing where the cord enters. Avoid water and don't use harsh chemicals.
Keep a note of the shutter type and housing dimensions. If you ever need a replacement cord, the handyman will need to know the shutter model and the drum diameter. A photo of the housing label (if visible) is helpful.
A stuck mechanical shutter is frustrating, but it's almost never an emergency. Take your time, apply gentle pressure, and don't force it. Most problems are either simple re-tensioning or a straightforward cord or spring replacement — both quick and affordable jobs for a professional handyman. If you've identified the issue and it's beyond a quick fix, a call to a local handyman will have your shutter working again within a day or two.
For a professional assessment and repair, contact a qualified handyman experienced in shutter maintenance in your area.
