Construction project of this volume feasible?

Correct, the maximum rate for civil servants during parental leave is 1800 euros.

Exactly... and after 12 months or at most 24 months with Elterngeld Plus, it is also 0 here! So I don't understand the OP's statement....

Regarding having children: The advantage for civil servants is that you receive a fairly high parental allowance.

Hello house-building friends,

I (34) currently live with my wife (32) renting (650€ all-inclusive). We are both teachers at the same school; I am the didactic head (A14Z) and she is a regular teacher (A13Z). We currently have about 6500€ net income, trend rising, up to 8000€ is possible. Monthly expenses are currently just under 3000€. We save 3500€ every month.

My wife has now received a fully developed plot (~1100 sqm) from her father, and we have talked about whether we want to build. We would like to build an energy-efficient, modern house with around 300 m² on 2 floors (2 children's rooms would be important, large living-dining and kitchen area (80m²), guest room). Also a terrace with pool and a roof terrace. As a reference, this picture serves:

Image deleted by mod due to missing source; construction expert

I have no idea what something like this would cost. On the internet, with upscale fittings, it said about 1800€/m², so that would be 540,000€. Additional costs should be around 25%, so another 135,000€
The pool costs about 30,000€.

I have now set a total cost of 750,000€ overall. Equity is 150,000€. That would be 600,000€ as a loan. According to online calculators, at a 3% repayment rate with a fixed interest rate for 20 years, that would be about 2,500€ per month. The remaining debt would then be about 160,000€.

Before we now approach a developer/architect, we wanted to ask here first to what extent you consider such a project feasible? Before the disappointment is too great.

Many thanks in advance.