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Tunnel Extensions: When and How Many?Updated 14 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?
Each frame lip is 46 mm deep. The standard Flappie frame (without extensions) fits doors and walls from 14 to 36 mm thick. For anything thicker, you add tunnel extensions.
How many do I need?
Each tunnel extension adds 27 mm of depth. Maximum 6 extensions.
Without mounting adapter
| Wall/door thickness | Tunnel extensions needed |
|---|---|
| 14 – 36 mm | 0 (standard frame is enough) |
| 36 – 77 mm | 1 |
| 77 – 104 mm | 2 |
| 104 – 131 mm | 3 |
| 131 – 158 mm | 4 |
| 158 – 185 mm | 5 |
| 185 – 200 mm | 6 (maximum) |
With mounting adapter
The adapter takes up 7 mm on each side (14 mm total), so the ranges shift down:
| Wall/door thickness | Tunnel extensions needed |
|---|---|
| 4 – 26 mm | 0 |
| 26 – 67 mm | 1 |
| 67 – 94 mm | 2 |
| 94 – 121 mm | 3 |
| 121 – 148 mm | 4 |
| 148 – 175 mm | 5 |
| 175 – 200 mm | 6 (maximum) |
The maximum supported wall thickness is 200 mm (6 tunnel extensions). Without adapter: minimum 14 mm. With adapter: minimum 4 mm.
Good to know
- 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.
- The 200 mm limit exists because the included flat cable only reaches that far. Longer third-party cables exist but are not certified by Flappie and void the cable warranty.
📹 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.