Construction costs for a single-family house with a basement in NRW

My question is now how much do we have to calculate for a house with 150 m² of living space plus a residential/utility basement? ... Equipment simple to medium-high quality Single and two-family house 1,100 EUR 1,350 EUR 1,800 EUR ... Does that fit? Is that with a basement? So with 150 m² plus approx. 80 m² basement, so 1350*230=310,500€ with medium equipment?

A new build is no longer so cheap in Viersen either. Are you actually referring to 150 m² of living space or total floor area?

Wow. Sounds good. When did you build? You are an outlier down here.

We built this year. But these are the prices from 2015. That's when we signed the contract. We built with Heinz von Heiden. They are among the cheaper providers. Some would even count them among the budget providers. However, I can't complain. A solid house, even after living here for half a year I can still say that. However, you can see a clear difference compared to, for example, Viebrockhaus. Neighbors built with them. Not only were they much better in terms of process and organizational scope, I also think the house somehow looks more high-quality. But that's just my personal feeling. My husband doesn't think so at all, or rather he attributes it to the fact that we did the painting and flooring ourselves.

307k outlier downwards?

That was a 170sqm bungalow without a basement!

1,800 Euro/sqm including additional construction costs

You want 150sqm + basement, right, or did I misunderstand something?

Drive through the country to Sieben or Schotes and see what they have on offer...

I still maintain that it will be more expensive than you currently imagine.

Uh, exactly. Silk weaver factory. I just would have looked at it.

Do you know that this 170 sqm house actually only has 140 sqm?

307k outlier downwards?

That was a 170sqm bungalow without a basement!

1,800 euro/sqm including additional construction costs

You want 150sqm + basement, right, or did I misunderstand something?

Drive through the country to Sieben or Schotes and see what they have on offer...

I still maintain that it will be more expensive than you currently imagine.

Yes, I do think so. The basement offers half of the usable space. I want to use the other half as a hobby room eventually. Although by now I’m wondering if that even makes sense.
Here, I’m being told around 450k for 150sqm with basement plus garage/garden etc. So I find 300k all in already much lower.
I need to think carefully whether 170sqm of living space without a basement, but with storage space in the attic, might not be the more sensible alternative.

140 sqm living area

Without basement, without attic, without garage.