Steps between kitchen/dining room and living room

One could also consider going 3 - 4 steps higher with the split and then going 3 steps down into the garden...

One could also consider going 3 - 4 steps higher with the split and then going 3 steps down to the garden...

In the current draft, however, it would probably only change that there are fewer steps inside the house. The problem with the ceiling height remains current. In my opinion, the OP should give up the unnecessary floor-to-ceiling windows on the 1st floor anyway. Then the roof of the extension could also be set significantly higher...

Yes, the visualization without ceilings is misleading,

I can make a view from the interior tonight.

One could also consider going 3 - 4 steps higher with the split and then going down 3 steps into the garden...

I wouldn't do that. Then there would be even more steps/stairs, also at the entrance area. I think one must not forget what the focus here is or what is actually wanted – namely a living space extension, because the house does not have enough area. Furthermore, the approach is to have the kitchen and dining at garden level. This results in a height offset that is connected with a staircase. In principle, one could now continue the wall, i.e., without a parapet to the other half-floor. However, that is also boring. Thus, the half-connection next to the stairs is offered. But now it seemingly becomes the actual core of the problem, the longer one talks about it. However, I consider that a wrong prioritization.

So, the extension probably doesn’t have to be 2.40, but I would be cautious with extreme height. Because then furniture can appear quite puny.

It won’t get so high that this danger threatens with this floor plan.

The lounge corner directly at the glass looks very cozy, simply a great idea!

Yes, wonderfully visualized by . The translucency benefits the living room enormously.

whether this looks good with a ceiling height of 2.60 or 3m?

Yes, that can look great. The choice of the front is important in such cases to avoid overpowering the narrow room. Large surfaces help but are somewhat more expensive if you choose a manufacturer whose fronts don’t eventually start warping. Carpenters can often manufacture to measure at reasonable prices. Have a look around locally.