Construction in the Munich district, realistic?

Good morning everyone, Thank you already for your answers. I’ll try to answer all questions. Yes, the plot alone costs €1,220,000. Unfortunately, this is absolutely normal here and definitely not the most expensive offer. However, the owner yesterday said we will see where we can come to an agreement. So we might still have a minimal bit of room to negotiate downwards. But of course, that does not change the rough calculation. The equity of 900k is a paid-off 4-room apartment, ground floor with garden. It belongs to my parents and they would include it 100% as a gift to my sister and me. As I said, we are still living there currently, so it would have to be financed in the meantime. There is theoretically a second collateral for the bank, namely my parents’ house (large plot in the Munich city area, value over 2 million). My sister and I are co-owners along with our cousins. However, our parents have usufruct on it. But they would guarantee for it. The loan of 650k per family is already clarified with the bank, we would actually each get up to 800k, but we would rather not go into debt that high. That’s why the question was whether you consider the sum of about 880k for a semi-detached house (living area about 140 sqm per half) + garage + additional construction costs to be feasible. Maybe a brief word about our income. We are three employees in the public service (all in senior service). And my brother-in-law is self-employed in the advertising film production sector. My parents (should they guarantee) are both still fully employed and also both in the public service.

Wait a moment. So the apartment is not equity but just bank collateral for the mortgage? Or will it be sold? Otherwise, you really get financed 650k-800k per person with an income from the public sector? You would need at least 4,500 net for that.

Building itself shouldn’t be that expensive though, you can hire craftsmen from outside.

True, why doesn’t anyone come up with that

But seriously. Honestly, I don’t think it gets that much cheaper if you hire craftsmen from outside. Because even outside Munich it’s not cheap.
We also know too little about the requirements and wishes to judge, info is also very sparse.
But even with €2,500 (which I consider barely sufficient for the Munich area from the start of the planning phase to probably the start of construction not before the end of 2021) and without a basement (I already suggested that, but got no response yet) it will be very tight.

140*2500 = 350,000

Then the question whether 140 sqm will be enough because the basement is gone. Maybe 20 sqm more is needed, which would correspond to about €50k again.

Garage = €30,000
Additional construction costs = €60,000
Fittings = €50,000

Total = €490,000

We are already €50k over budget. Without a buffer, basement already omitted, no basement replacement area calculated, in my opinion €2,500/sqm is still too tight