A door chain is a short metal chain with mounting plates at both ends, fitted across a door and frame so the door can only be opened a few centimetres (typically 5–10 cm). It is used as a visual check at a front door: you can see who is calling without opening the door fully.
How it works
The chain comes in two parts:
- A slide track or hook — mounted on the frame
- A chain with a slider knob — mounted on the door, with a sliding piece at the end
When the door is closed, the slider sits inside the track. As the door opens, the chain extends until the slider reaches the end of the track. To open the door fully, the slider is lifted out of the track.
Where it is used
Door chains are typically fitted to:
- House front doors — to identify callers before opening
- Hotel room doors — as an extra layer beyond the lock
- Back doors — for evening use
- Student rooms — for added privacy in shared houses
Security considerations
A door chain offers only limited security. A determined intruder can usually break the fixing with a single forceful kick. For meaningful burglary resistance, consider:
- A door restrictor — a sturdier all-metal device that takes much more force
- Combining it with a multi-point lock
- Fixing the chain with long screws into both the door and the frame (not just the architrave)
- Making sure the frame is properly anchored to the wall
Door chain versus door restrictor
| Feature | Door chain | Door restrictor |
|---|---|---|
| Material | Thin chain | Solid metal arm |
| Burglary resistance | Limited | High (often certified) |
| Operation | Manual sliding | Sometimes key or thumb-turn locked |
| Lifespan | Limited | Long |
| Look | Traditional | Modern, more robust |
Installation tips
For best effect the chain should sit at the right height — typically 130–150 cm above the floor, near the lock. Mount the slide track on the hinge side of the frame (not the lock side) and the chain horizontally on the door leaf. Use screws of at least 30 mm to ensure good grip.
Related terms
- Hardware
- Door restrictor
- Multi-point lock
- Anti-burglar hardware
- Door
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