I have added it once. After various considerations, I have come to the conclusion that I will use sliding windows. I still have to speak with the window manufacturer, but just the fact that they do not protrude into the room makes it worthwhile for me. I also think that a fixed element and an opening element, which is almost 1.5m, is enough to allow sufficient air circulation.
Since these are dormer windows, I also want an externally mounted roller shutter. A colleague told me that the roller shutter/roller shutter box also has to fit in this 1m high opening. It’s quite disillusioning... I thought the roller shutter/roller shutter box could be mounted a bit higher (at least partially), towards the roof itself for space reasons. Can someone clarify this for me? I only have an appointment with the window manufacturer next week and am slowly fearing to end up with only 40cm of glass. Besides the space gain through the dormers, I was also hoping for more light.