Velux Window Extension Hook (2016+) - 3 sizes

Extension hook for Velux windows (2016 and Later)

My Velux windows are fitted with Velux roller shutters. However, I never got around to adjusting the spring tension to account for the added weight of the shutters. As a result, the windows won’t stay slightly open when the shutter is down. Given that we sometimes get strong winds, I was hesitant to adjust the spring tension and leave the windows even slightly open, out of concern that a gust could force them fully open and possibly cause damage.

I came across a model by duckydk's, originally designed to route an airbrush ventilation hose through the window. Unfortunately, his model was made for pre-2015 Velux windows, while mine were installed in 2016.

As expected, the original model didn’t fit—but it gave me enough of a starting point to create a remix that works with 2016 and newer Velux windows.

July 2025 update:

• The short hook was improved with a 25mm hole to allow it to be hung to the Velux handle. My hook was constantly misplaced, now it has a designated place!

• As many of you requested, I designed a longer version. 
  The model was increased by 50mm and went through several prototypes as it could no longer work in the same way as before : without the “leg” at the back, the hook could get lose and fall.
  The longer version also includes a 25mm hole for hanging, and has 2 internal reinforcements (tiny pockets forcing the slicer to generate extra walls).

  Due to the different shape, I put the longer version on its side in the slicer, and use supports for some of the overhang. There may be other way to print it, let me know if you find a better one!
  I have tested it on my Velux (3 different sizes), it should work on most Velux GPL series.
  The longer version is NOT compatible with Velux GPU series as the Velux strike is not in the same position, the “leg”does not rest correctly.

• An intermediate cat-friendly version was requested, I just added it to the set.

   

  The effective opening for each extension hook is:

  • Short : about 25-30mm
  • Mid : about 50mm

  • Long : about 80mm

     

Compatibility:

• Compatible with 2016 and beyond Velux
• Compatible with GPL Velux frame
• Personally tested on GPL SK06, GPL SK08 and GPL MK04
• Should work with GPL CK04, GPL PK04, GPL UK04, GPL CK06, GPL FK06, GPL MK06, GPL PK06, GPL FK08, GPL MK08, GPL PK08, GPL UK08, GPL MK10, GPL PK10, GPL SK10, GPL UK10 and GPL MK12
• The long hook version is not compatible with GPU Velux frame due to striker placement (checked on my GPU MK04)

Usage:

As shown on the image, slide the hook into the strike locking grooves. 

The Velux can be closed and it will remain locked in that position. 
 

Note:

Printed in PLA, working absolutely fine considering the forces at play. It's a lose fit in the grey Velux locking mecanism, and a slightly tighter fit in the GPU strike.

Please let me know if Velux has made further changes recently or if you have any issue with it.