Additional costs (this is off to a good start)

I can only agree with Mycraft. We compared eight home construction companies - surveying work was never included. Most were honest enough to tell us beforehand and included it in the incidental construction costs. 1-2 only upon request.

With our GÜ, the staking work is naturally included! I would have been very surprised if that had been extra. The surveying afterwards, of course not, since that is done by the surveying office anyway (at least in Bavaria).

whether staking is included in the price or not can be seen in the construction description. you should read a handful of construction descriptions anyway, because each one contains something new and where you want to sign, you should go through line by line and ask the company about questions or missing information (see other BB). all of course before signing.

if you are then convinced you have found all additional costs, you will only be surprised by 3-4 items in the end. if you do nothing beforehand, you should have a big buffer.

I can only agree with Payday. Read line by line. When we received our house construction contract, I had prepared a 10-page questionnaire. Many questions could be answered with yes or no, others required a detailed explanation. Everything was documented in writing. Our consultant was very happy about this, as neither side wants major surprises. Nevertheless, additional costs cannot be completely avoided. Our foundation builder is now finished. We had estimated €12,000. The invoice comes to over €15,500. We have calculated a buffer of about €50,000 and hope that this will be enough in the end.

Hello Stefan G., we are also about to have to compare different construction descriptions. Is there a checklist somewhere on the internet that one can roughly orient oneself by? We are already very excited about the offers and first drawings that should arrive at our house in the next 1-2 weeks...

Google search for "Checkliste Baubeschreibung".
Links are bad here.