Cost of painting interior walls/ceiling

an uneven ceiling is, among other things, the ugliest thing there is in new construction.

Agreement! From the sofa I currently always look at an uneven part of the ceiling and get annoyed about it every time.

Uneven ceiling is relative, during the day you don't see anything but with light you can see waves in the ceiling here. Doesn't really bother me, I find the uneven walls much worse. But when I read the prices here, I just say OMG. Better crooked walls...

Short question: What is the advantage of Q3 plaster under the wallpaper? We also have Q2 included in the contract and are considering wallpapering directly over the Q2 plaster. Is that not possible?

You will find the differences listed in the search engine of your choice. For many, Q2 is sufficient (if well done, there are also differences there), Q3 and 4 are rather for when no or very thin wallpaper is applied.

We have had very different experiences with Q3 work. When building the house, we paid quite a lot and got a, I would say, result you shouldn’t look at too closely. You could still occasionally see the putty spots from the screws. Last year, we closed off part of the airspace in the house and created an additional room, where we used a different painter who was considerably cheaper but worked much cleaner. I look at one wall from the sofa and don’t see a single unevenness. Long story short, look for a good painter from the nearby area. It is usually cheaper as well.

We have now reached the point where we were able to inspect our plaster. The Q2 plaster from the general contractor is (in my opinion) very good for Q2. Here and there a small detail, but overall very solid. Today I had a walk-through with a painter we are considering hiring. He also explained some things to me that were not clear before.

We are now considering hiring him for just under €6000. The price includes travel, labor, and all materials. We discussed with him that we want a lightly textured non-woven wallpaper instead of a smooth one. There are also nicer patterns than the classic "coarse woodchip." He will then sand once, prime, wallpaper, and paint the walls.

I asked whether it would be possible to wallpaper with a sample wallpaper or a plain non-woven wallpaper in the desired color. He said he advises against it because it would not look like the photo in the end. He said the preview images on the internet always have a perfectly smooth, single-colored wall as the basis. If we wallpaper over our plaster like that, the color differences would show through since the non-woven wallpapers are always slightly transparent. Therefore, he recommends wallpapering and painting.

Do you think the price is fair (it seems so to me)?

How many square meters of ceiling and wall surface are there?

We are also currently obtaining quotes. It all seems reasonably priced to me. But it can only be assessed based on the square meters. For us, smooth fleece probably costs 7.8 Eur/sqm and painting 5.10 Eur/sqm, each plus tax.