Is building a house financially feasible?

So a plot between 50,000 and 70,000 euros.
Plus land transfer tax of 2,500 to 3,500 euros. But only as long as you buy the land and house separately. Otherwise, the tax also applies to the purchase price of the house.
Plus notary costs of about 1,000 euros.

With a budget of 250,000, there remain for the house in the "best" case 196,500 euros and in the "worst" case 177,500 euros.
Based on 130 m², that is in the best case about 1,511 euros per m² and in the worst case 1,365 euros per m². The 1,511 euros is very tight. 1,365 euros will definitely not work. Keep in mind that construction costs have risen extremely sharply in recent years and will continue to do so as long as the interest rate remains so low.

Therefore, I think your maximum budget of 280,000 euros should definitely be your absolute minimum budget. Outdoor facilities, garage/carport, etc. are not yet included in that.

Nevertheless, I think that with your income you can realistically approach building/buying a house. The second child will of course complicate things significantly! Are daycare costs for child 1 already foreseeable?

Oh yes: I have no knowledge at all about [Erbbau].

Who would be the provider of the leasehold land?
Not everyone is approved by the financing bank

The positive aspect is that you do not have to finance the money for the land - the lease payment corresponds to the interest you would have to pay if you were financing it, but you do not have a repayment installment.
Disadvantage: after 30 years, the lease payment remains... you pay it your whole life.

So you are more flexible now and can afford more, but later you always have the lease payment.

We also have a leasehold property ([Klosterkammer], 80 years, flexible adjustment of the rate) - we do not see the problem in always paying this small rate and were able to afford small nice extras this way

Regards Yvonne

So let's better calculate with 280,000, that is probably more realistic. I haven't really thought about the outdoor facilities yet. Of course, that is also an item that costs a lot of money.

We are already paying [Kitagebühren] for child 1 and have included them in our fixed costs. Therefore, we can also estimate what additional costs would come up with a second child.

The provider of the [Erbbaurechtsgrundstücke] would be the church. My main fear is that we might overlook something and the contract does not actually last the 80 - 99 years. And hypothetically, if the church says at some point, they are selling the plots after all, we would certainly have to pay the full land price. So there would be no credit for the lease payments made so far. Am I seeing that correctly?

So with the churches you are definitely on the safe side with the leasehold. They calculate in centuries. The main providers of leasehold are churches. Precisely because they do not want to sell their properties. For a company, 100 years is a long period, but for a diocese it's a piece of cake, who knows, maybe the property can be used again in 200 years...

You have several tens of thousands of euros more available because of the leasehold. And you also save on property tax.

Property tax must still be paid! Even with [Erbpacht].

True, that's what it says in the [Grundsteuergesetz]. Not necessarily logical, but okay. I didn't know that. Learned something new.