Interesting house construction offer? Experiences?

Arrange the rooms on paper, check if the power outlets are sufficient - sounds borderline okay. 10 - 20 more probably won’t hurt. Do you have a lighting concept? Ceiling outlets are, for example, rather difficult for ambient lighting and who wants full lighting for cozy TV watching? You should also plan switchable sockets... in short: a little extra cost will be added there ~ 2000 €
Q2 plaster cannot necessarily be painted directly, wallpapering and/or reworking is required here. ~ 3000 €+
Ceilings painting / filling ~ 2000 €
Floor coverings also cost at least the material costs if laid by you 3000 €+

Sat included?

Thank you! I just realized that it is not included. I can do it myself, but retrofitting the cables would be a disaster... Whether the LAN sockets are double sockets cannot be deduced from the description. I suspect they are single ones....

Ceiling painting / filling ~ 2000 €

We also forgot that. For the other costs, your advice matches our calculations.

It is a house according to the 2009 Energy Saving Ordinance, so not a KfW55.

Well, at least the 2016 Energy Saving Ordinance must be achieved

etc. In total: 24 single sockets, 16 double sockets,

The kitchen is important. 6 more. And have the single sockets near the light switch moved lower. And it always turns out different with the furnishing, so don't save here. Later you can convert single sockets into double sockets

Q2 plaster can't necessarily be painted directly, here you have to wallpaper and/or do touch-ups. ~

Yes, you can. Only fastidious people who grew up with woodchip wallpaper find it insufficient.

Think of outdoor sockets and outdoor lighting... oh, what am I writing: look at the dozens of posts, also the pinned ones in the Construction Costs section. Then you will also know what else might come.

Hey, ypg, thanks for your post. In a moment of mental confusion, I wrote 2009 instead of Energy Saving Ordinance 2016.

Naja, mind. Energieeinsparverordnung 2016 muss erreicht werden

I have corrected it for posterity.

Outdoor light, faucet, outdoor socket are included.
Thanks for the numerous tips

LAN and Access point: Our access point, only have one!, more unnecessary, plugs into the socket and is from Devolo. Works perfectly.
Socket at the light switch: This is indispensable for us, who wants to keep bending down every time when plugging in a vacuum cleaner or something similar?
Q2: Needs to be re-spackled. But it’s not a big deal.
Ceiling spackling is another level: You should be able to get painting work done for around 6000,- from a one-man craftsman, including spackling. Floors: 2000 material, 600 labor. Was enough here. Through a company with tax.
Tiles 60*30 to 25 are okay. You can find something there. The number of sockets is close to enough.
Don’t get fazed by those who only know the top shelf. It works.

Tiles: 25€/m is basically enough. We managed very well with it and even got 300€ back. But we also didn't choose any special sizes. However, keep in mind that the baseboards are never included! Either you get lucky and there are enough tiles left over so the tilers can do it under the table for little money, or you have bad luck and it's not enough.

Electrical: Make a precise plan now of where you want which outlets. Otherwise, it's very easy to miscalculate. The same applies to Sat ([Sat-Schüssel]) and LAN. Also keep in mind that no toggle switches are planned for the light switches. They can get expensive quickly.

LAN: They almost never include finished network cabling. So you have to arrange a patch panel with router connection yourself. Not rocket science but it costs money too.

Floor work: You won't know exactly what to expect until you have the floor survey. We did it earlier (without signing the contract, basically "paid ourselves" initially). They charge for it later.

Sanitary: For the walk-in shower, be aware that they plan a central outlet. That forces you to use mosaic tiles on the floor. If you want that stylish edge outlet, you have to expect roughly 1000€ extra. Also consider whether you want concealed fittings. That also costs more. The standard planned for sanitary installations doesn't suit everyone. Treat yourself to a sufficient budget there.

Roof: The roof shingles are usually the simple ones. It might make sense to choose shingles with a special coating. Then the green algae won't build up as quickly. Depending on roof size, that can easily cost 1000€ more.