Here are some current photos from today.
The boxing in for the entire exhaust pipe (including the offset) will be about 50 cm!
There were also ideas to only box in the part at the wall and then box the offset separately, but me and the sanitary guys don't think it would look better with yet another corner in it.
The toilet is now positioned based on this boxing, so it has moved quite close to the bathtub.
Unfortunately, I haven't reached anyone at the house construction company yet, but I think the situation will unfortunately not change anymore.
The offset is due to building constraints, and a repositioning of the pipe would probably have had to be tackled much earlier.
