I’ll just write it here again since it is related to the possible financing.
Thanks again for the tip regarding the construction costs: We had the construction service specification reviewed by an expert regarding the construction costs, and there were still a few items that we have to bear.
The question, however, goes in a different direction: The notary contracts from the municipality are scheduled for September/October. Construction is then planned to start in April 2017.
In further discussions with banks, the problem arose that due to the longer waiting time between the purchase of the land and the start of construction, the interest-free provision period is not sufficient. So far, only one bank (the one from the first post) agreed to a longer period. According to the advisor, there is no other solution to this problem than to pay these provision interest charges in case of doubt. Is there really no other possibility?
A second bank would offer 1.79% interest, but only with 11 months of interest-free provision period. Honestly, I don't really have a sense of when and how much has to be paid in order to roughly estimate whether it makes sense or not.