I think you first want some security and to ask around whether this project is even feasible.
Furthermore, you probably want information on how you should/must/can proceed in the next few weeks in order to secure the plot as quickly as possible and not forget anything important.
I can take away your fear and give you the (I think most important for you) information:
- Your income with 2 children is good and your equity is also good --> with that, you can definitely fulfill the dream of a single-family house
- With €1,800 you can roughly manage the loan amount - of course, it depends on how much equity you want to use --> we have slightly higher costs for our overall project and even significantly less equity and a repayment rate of €1,600-1,700 - of course, it also depends on the term - it depends on how long you want to pay off. Nevertheless, still realistic!
- Consider carefully whether you want to pay for the building plot directly from equity. Definitely sensible, but you should also calculate enough buffer and always have some money set aside, since you also want to do things like the carport (possibly also the outdoor facilities?) afterwards. With children, you should always keep some equity aside. I would actually recommend financing the plot variably and then calmly looking around for a builder. The interest rates for variable loans are currently very good and so you will also be flexible in financing the overall project - you can then look around again and possibly do everything with another bank. I would then pay the incidental construction costs from equity and take out a loan for the rest.
- 160m² is initially not really meaningful... Are you planning with a basement? What exactly are your ideas? KfW 40 house? KfW 55 house? Prefabricated house/masonry? Ventilation system? Photovoltaics, etc... These are some points that can drive the house costs up. For €300,000 you really don’t get anything "great," or really only the "minimum" - I even suspect that you won’t get a 160m² house anywhere for this. I would definitely set a minimum of €350,000-400,000! The incidental construction costs then amount to about €50,000.