Is a house for a total volume of 400k still possible at all?

Also a reason why I’m asking about brush-on plaster.
What can you compare a 0.5mm grain to? 100-grit sandpaper?

We had 1mm brush-on plaster from Haering in the house, which we thought was great. You can color it directly or leave it white and then glaze it as you like. At the ceiling, I once tried 2mm... that idea was less good because the ceiling and the 2mm were not easy to spread... for me.
I think the 0.5mm product can still be sprayed with a machine. If I do it again with a brush, I’ll go for the 1mm again, which I liked.

Possibly still a textured plaster like . Color with mixed-in sand. There is joint sand in smaller grain sizes than 0.5.

However, I think the problem is getting the whole thing evenly onto the wall. It didn't really work in my basement. But that was probably due to the formwork oil.

You just have to keep stirring the bucket well and then use the wide brush with a cross stroke. I did it for the first time back then and it worked wonderfully. Maybe it was also due to the manufacturer, but it was definitely easier than expected for once.

There were two of us. My brother rolled. I had a ceiling brush in my hands, with which I swept in crescent shapes, big crescents. It looks quite good when dry.

Thank you for the tips, you are, as always, great! With my wife, I can’t get those wiping techniques through. She just wants a smooth white wall and one decorative wall per room (but she wants to do that herself, it’s already agreed). Maybe I can get my father-in-law involved to do one half with painting fleece with me, and then maybe I can manage the rest myself. We’ll see, there’s still some time.

I am not comparing at all, I just don’t understand why people are focusing specifically on the teachers.

... because the OP pretended to be a teacher and mentioned high numbers. That was the straightforward setup.

I would have absolutely no problem justifying the costs of a 1 million house in a reasonable argumentative way ;)

Hehe... probably off-topic here.

I can’t get away with such wiping techniques with my wife.

Wiping technique: That used to exist. It’s not current again like retro or something.