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Tunnel Extensions: When and How Many?Updated 21 days ago
If your door or wall is thicker than 36 mm, you'll need tunnel extensions. They click into each other like building blocks and extend the depth of the Flappie frame so it reaches through your installation.
When do I need tunnel extensions?
The standard Flappie frame has a depth of 47.5 mm and fits doors up to 36 mm thick without any accessories. For anything thicker, you add tunnel extensions.
How many do I need?
Each tunnel extension adds 27 mm of depth. Here's a quick reference:
| Wall/door thickness | Tunnel extensions needed |
|---|---|
| Up to 36 mm | 0 (standard frame is enough) |
| 37 – 63 mm | 1 |
| 64 – 90 mm | 2 |
| 91 – 117 mm | 3 |
| 118 – 144 mm | 4 |
| 145 – 171 mm | 5 |
| 172 – 200 mm | 6 (maximum) |
The maximum supported wall thickness is 200 mm with 6 tunnel extensions.
Good to know
- The number of extensions may vary slightly if you're also using a mounting adapter → — measure your actual installation depth to be safe.
- Only use original Flappie tunnel extensions. Third-party parts don't fit precisely and may cause leaks or instability.
- Tunnel extensions are sold separately in the Flappie shop.
📹 Tunnel Extension Video: Watch on YouTube
Not sure how many you need? Write to [email protected] with your wall thickness and we'll let you know.