Garage door problems
Why your garage door won't close
A UK garage door that won't close is most often a blocked or misaligned safety photocell, which under BS EN 12453 stops the door as a protective measure. Drifted operator limits, a worn cable and track obstructions account for most of the rest. A call-out typically runs £40–£80, and many faults need no parts at all.
Work through the checks below in order — they run cheapest and safest first, from a five-minute lens wipe through to jobs that need an engineer.
Check the photocells first
Every power-operated garage door installed in the UK to BS EN 12453 has a safety photocell system that stops the door closing if the beam between the two sensors is broken. They sit roughly 150–200mm above floor level on each side of the opening. A cobweb, a smear of garden dirt, direct low winter sun hitting the receiver lens, or a bike leaning against one unit is enough to trigger the fault — the door will start to close and immediately reverse, or refuse to move at all.
Drifted or lost operator limits
The operator (the motor unit, not to be confused with the door leaf itself) learns two limit positions — fully open and fully closed. A power cut, a firmware reset, or simple mechanical creep over months can shift the closed-limit setting so the operator stops the door a few centimetres short, or thinks it has reached the floor when it hasn't. This shows up as the door closing partway then stopping, or refusing to start the closing cycle at all.
Physical obstructions and track problems
Check the full length of both tracks for a dropped tool, a stone, a build-up of leaves, or a bent section — roller doors are especially prone to debris in the side guides. On sectional and roller doors, a single misaligned roller or slat can bind hard enough to stall the motor before it reaches the floor.
Worn or slack cables
On up-and-over and sectional doors the lifting cables run under constant tension. A cable that has begun to fray or has slipped off its drum will let one side of the door hang lower than the other, jamming it in the tracks before it can close. This is a mechanical fault, not a safety-system fault, and it needs an engineer.
| Cause | DIY fixable | Typical cost |
|---|---|---|
| Dirty or misaligned photocell | Often | £80–£180 |
| Drifted operator limits | Sometimes | £0–£180 |
| Worn or slack cable | No | £120–£250 |
| Bent or obstructed track | No | £100–£220 |
Prices include VAT. A call-out fee of £40–£80 may apply on top. London and the South East typically add 15–25%.
Step by step
1.Clean and align the photocells
Wipe both lenses with a dry cloth and check nothing — a bike, a bin, a shadow — sits in the beam path between them. Nudge each unit gently and check the small indicator LED (where fitted) shows a steady, not flashing, light.2.Clear the tracks
Run a torch along both tracks from top to bottom looking for debris, a bent section, or a roller sitting proud of the channel.3.Re-learn the operator limits
Most operators have a limit-setting sequence in the manual, usually a button held for several seconds. Follow it exactly — an incorrectly set closed limit can cause the door to over-travel and strain the mechanism.4.Inspect the cables
Look at each lifting cable from a safe distance for fraying, kinks, or slack where one side has slipped off its drum.Safety: Never attempt to adjust, tension or release a garage door cable or spring yourself. Both store enough energy to cause serious injury and require an engineer with the correct winding bars and clamps.
Questions people ask
- Why does my garage door close then immediately reopen?
- That is the safety reversal system working as designed under BS EN 12453 — the operator has detected an obstruction or a signal fault and stopped the door rather than risk trapping something. In most UK cases this is a photocell fault rather than a genuine obstruction, so clean and check the lenses before assuming a mechanical problem.
- Is a garage door that won’t close a safety issue?
- It is usually the safety system doing its job correctly, not a fault in itself. Only proceed to manual override or forced closing if you have checked the photocells and beam path first — never override a safety reversal repeatedly without finding the cause.
- Can I fix this myself or do I need an engineer?
- Photocell cleaning and limit resets are safe DIY jobs on most UK operators. Anything involving cables, springs, or a door that has come off its tracks needs an engineer — a call-out typically costs £40–£80.
- Does cold weather stop a garage door closing?
- Yes — in the UK, low winter temperatures can stiffen grease in the tracks and rollers enough to trip the operator’s force-limit safety cut-out, which under BS EN 12453 stops the door if it meets more resistance than expected. A light silicone-based lubricant on the tracks often resolves this.
UK standards and regulations referenced
- BS EN 12453:2017+A1:2021
- BS EN 12445
- BS EN 12635
Related
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