Material costs painting single-family house new construction

Thank you for the explanations. I had apparently simply misunderstood you regarding the 150m², as you obviously mean the floor area of the rooms to be worked on, and I was thinking of the area to be painted.

The OP mentioned 150 m2 of living space. So clearly more area to paint...

Keep in mind that you won't find a simple price per square meter because requirements also vary. Walls cost about 20% more with fleece. With woodchip wallpaper, the price is the same if well filled and painted. Glass fiber plus latex in damp rooms is intense. However, it replaces tiled areas and is fully scrub-resistant. Small embellishments, stucco moldings, and such make it special but cost extra. White lacquered stair railings and similar things really hit the budget. And so on.

But what does it look like if you putty drywall Q3 and then paint it directly, has anyone had experience with that? Treat with primer beforehand and then it should work, except for possible cracking, right?

Yes. But I am not satisfied with it. It looks good at first, then cracks. In my opinion, there must be a fleece on it. When we renovate the stairwell, we will do it like that.

But then Q2+fleece+coating would be sufficient, right?