Financing: Our house construction project is scheduled to start next year

The only difference is that with a complete renovation you never know how much money you will still have to invest, and you live on a half-finished construction site.

You renovate before you move in...

Of course, you should have the costs generously planned in advance. By someone who knows old buildings --> architect. The same applies to new construction. Your previous cost estimate is also way off target.

Again: new construction has a lower limit of 2k, not an average. And that is of course all without additional construction costs like earthworks.

Well, as I said, I’m going my own way, I appreciate your advice, and when we have found something or it goes in a certain direction, I will report here.

Your optimism is admirable, but unfortunately your income currently does not allow for this freedom in planning. You really have to plan properly in advance, and not only afterwards when you have found something. Otherwise, there will be really nasty surprises.

So we find our 20-year-old house for 350k euros,

Where a 20-year-old house costs 350,000€, a new build costs 400,000€!

I started the household ledger today,

That’s great!

AVERAGE 1630€

Nope!

as written below I don’t want luxury,

Standard! Standard is at least currently 2000€/sqm

I do think you can get something for 330k€

Less than standard

many friends are skilled in craftsmanship

Skilled is not enough to save money.

Of course, I don’t need a fitted kitchen for 20K nor marble tiles. But a nice floor covering, nice modern tiles and a room layout I like (open living-dining area with access to the kitchen) is enough for me.

That also costs money, more than 1630€/sqm

I have always lived modestly and never bought anything beyond my means, because that’s how I was taught.

Of course you are modest. But your girlfriend is not! You say that yourself between the lines.

They are looking for 2 years+ for a plot of land, why shouldn’t we already start next year.

Why not start now already?

Just sitting around doing nothing and waiting to be thrown money at won’t happen.

That’s exactly what you are doing ;)
You haven’t really studied the matter. You should do that quickly if you are dealing with certain numbers and juggling them.

Full renovation, never know how much money you still put into it

First comes modernization, 20-year-old houses or somewhat younger usually don’t need renovation. Unfortunately many have thought like you. At some point you realize that you don’t get anything for your money on the market.
But that’s okay. You learn in life that used things also have their full value, just with different emphasis.

Be careful not to be lured by the market — you are a good customer because of your naivety, who lets himself be lured without hidden costs but then has to pay dearly because he didn’t inform himself beforehand about how the market works.

I live in a STILL affordable area and even here, €2,000 per sqm is the absolute minimum you can realistically calculate with. More realistically, it’s around €2,200 per sqm. On top of that come additional construction costs, purchase incidental costs for the land and exterior facilities (terrace, paving, lawn, fence, trees, bushes, external cables, shed, carport) plus furnishings including kitchen.

House: 2,200 x 150 sqm = €275,000

Additional construction costs: €50,000

Furnishings: €15,000

Exterior facilities: €15,000

Land: €120,000

Purchase incidental costs: 8.5% x €120,000 = €10,000

TOTAL: €485,000

You MUST at least calculate with this amount for a 140-160 sqm house without a basement and major frills.

And based on your information, I see this as not feasible for you. Because I believe the expenses will be higher on average per year than you indicated. However, the household budget book will show this if it is kept consistently for 12 months.

Are young people who can do everything already born from the sky?
I have already dealt a lot with this topic but I don't want to write 1000 lines.
And yes, the calculative skills could be a bit better, I know :D but as I said, the household book will show that.
From what I hear here, I think everyone wants to stop me from it. Did anyone stop Bill Gates from founding Microsoft? No?
And no one will be able to stop me either. Most 25-year-olds waste their money on cars, etc. I prefer to save my money and want to live in my own four walls in the future. Yes, I know that our income is still maybe quite tight at the moment, but should I throw everything overboard because of that? No. Do I want to live in a condominium? No, I want to build a house, which is my dream.
That's why I have educated myself further and if necessary I will continue to educate myself until the salary is there. My girlfriend also understood that and is starting her further education this year, and with that, her income will also grow next year. As I said, thanks for the comments :)

As I hear this here, I think everyone wants to stop me.

Why? We advise you on what you can do. But we cannot confirm your numbers – they definitely need to be corrected here by experienced people.

No one wants to talk you out of your dream home. Really not. We are just warning about the high costs. If you want to be proactive, then make an appointment tomorrow with the [Hausbank / Finanzmakler] and inquire about your maximum loan amount (and what kind of house you can get for that).