Calculation of Property Purchase and Renovation

We would live in the 4 rooms upstairs and leave the ground floor as it is for now.

So you just want to leave the ground floor empty or do you have plans for it? I would reconsider whether you really want to buy a house where you only use half of the living space and the rest just sits there unused. Or is the plan then "we would move into the upstairs while we renovate/refresh the ground floor"?

Yes, exactly. The upper floor can be made ready to move into faster and more easily and has a layout that is more suitable for our needs.

The ground floor has a conservatory that is very nice in the warm season.
There is also a second bathroom that we can use.

Additionally, the ground floor offers 3 rooms that, after renovation/beautification, can be used as an office, hobby room, guest room, or children's room. The need and imagination are there. But there is no urgent necessity for that at first. We would be moving from our 4-room rental apartment into the 4-room house with a courtyard, garden, and garage. That is initially a gain in quality of life.

There is also a kitchen on the ground floor, but major interventions for electricity, water, flooring, and room layout would be necessary (maybe in ten years when all other things have been done).

I have a little more than 5k net and since the construction I can hardly save anything anymore, on the contrary, I really had to dip into the reserves. (...)

True story. I expect to be able to save a noticeable amount again at the earliest in 2025, also around 5k net and a 1,200 EUR installment. 2 kids, wife works 50%.

Just bought pleated blinds for all windows, 1,600 EUR... and that adds up...

PS: Don’t know you. But you’d be the very rare ones who really transfer a rental flat 1 to 1 into their own home, install a DIY kitchen for 5,000 EUR and then are satisfied. My wife also told me you could just take everything with you at first, no problem. Shortly before the move, though, everything was ordered new and the old stuff given away, etc.

All the electrical work was agreed on. That will be a lot of work...

True story. I expect to be able to save anything notable again at the earliest in 2025, also around 5k net and a 1,200 EUR installment. 2 kids, wife works 50%. Just bought pleated blinds for all windows, 1,600 EUR... and it all adds up...

Oh no! How badly off are you. Only able to blow through €3,800 every month – how do people live who maybe only have €3,800 net? And have to buy such expensive pleated blinds. No wonder hardly anyone can build/buy nowadays if you can’t hold back a little on living expenses. *Irony off*

Some things also resolve themselves. If you don’t have money for pleated blinds, you just manage without and lower the roller shutters ;)

But from my own experience, I can only advise being honest about your wishes from the start. It’s easy to say you don’t need much and do everything cheaply. In the end, when you’re at the sampling stage, you don’t want to live with the cheap solution for the next decades just because of 1000 or 2000€. Those thousands add up over time. Or you simply overlooked certain things in the calculation. Or you can hardly imagine how expensive a few sanitary matters are. In renovations, a nasty surprise can come unavoidably as soon as you open up walls somewhere. When dealing with a house, you’re dealing with large sums and it’s understandable at the beginning to try to keep the numbers as low as possible. But you’re not doing yourself any favors if you’re dishonest from the start and later try to finance things out of your current salaries. This especially applies to the topic of serious renovations. The corresponding obligations will certainly come in the next years, whether directly from our government or indirectly played by the EU [in other words].

But from my own experience, I can only advise to be honest about your wishes at the beginning.

Yep.
1. Do I want my own property? - yes or no
2. Can I afford my own property with my wishes and lifestyle? - yes or no
3a. If the answer to 2. is no, do I want to give up wishes regarding the property? - yes or no
3b. If the answer to 2. is no, do I want to make sacrifices in my lifestyle? - yes or no

You just have to keep in mind that, for example, giving up the Bundesliga streaming subscription (Sky+DAZN) and Netflix/Disney+ or similar can easily lead to being able to afford an additional €15,000 loan at today's interest rates.