Building a residential/hobby basement underground - What to consider?

5000 EUR...you don't really believe that yourself!!! One more zero What do we want to bet?

If really everything can be done in EL, which I cannot imagine, then I estimate at least €30,000. If parts without EL, then of course more.

A friend recently built and got the basement for 20,000 euros with a floor area of 80 sqm. That would be 250 euros per sqm.

First of all, that is an extremely low amount of money. He probably received little more than a hole and concrete for that. Secondly, the rule of three doesn’t make sense here. The 20,000 euros include things like stairs, and you have significantly more walls in relation to the area.

You can expect to pay between 50,000 and 100,000 euros for a normal basement (not a living basement!). Of course, this always depends on the local conditions (cost structure, soil...) and, of course, also the size.

But in my opinion, you can't get a basement anywhere nowadays for 20,000.

50k, I can go to the gym with a swimming pool and sauna for a few years

Well, I can't say more than what I have seen. And for 20,000 euros, that was a complete basement including ceiling and everything. We received an offer from a local construction company for 150,000 for a complete house with 140 sqm living space including a fully basement. So I can't imagine some statements here about 100,000 euros for a basement, sorry. This is only about a room of 20 sqm.