Idea not feasible due to residential basement?

Hello everyone!

After reading quite a bit about basements/living basements/square meter costs in this forum over the past few days, I thought it would be good to get your assessment of our construction project.

In short: Are we imagining something here that doesn’t fit our budget?

Our basic conditions are still quite loosely defined, as we are still very much at the beginning and only submitted an application for the planned development area two months ago. Apparently, however, there are good chances of getting a plot there; so maybe the allocation will start by mid/end of next year. The whole thing is supposed to take place in a rural area in NRW.

[*]Planned is a 1.5-story single-family house with a basement apartment
[*]The development area is on a slope
[*]The parents are supposed to move into the basement and get a living area of 80 sqm. Another 10 sqm are planned as utility space (technical room, storage room)
[*]On top of that, as mentioned, a 1.5-story single-family house with about 120 sqm
[*]The basement is supposed to protrude somewhat to the south (towards the slope) to offer a small terrace to the ground floor.
[*]We don’t have to pay for the plot, as it is being covered by the parents. Nevertheless, we can expect a typical two-thirds rent (+ rent for the parking space = at least 500€). That’s already nice
[*]oh yes: Both in prefabricated construction. Due to various circumstances, the small, quite fixed or plannable time frames “when everything is ready” are important for all of us.

Basically, that’s “about it”…..although I really didn’t expect the living basement issue to put us in such a fix.
The plan was a budget for the house of 300 to 350 thousand euros. Not turnkey, but each “almost finished.” Doing the floor coverings ourselves, walls, etc. Especially for the basement, since my father and I also finished the current basement of my parents on our own. If the single-family house, we thought, could be set up turnkey on top and everything is still within budget: all the better. Well…wrong assumption?

We have already received two initial offers, and we are still waiting for two more. In both, the basement amounted to about 60k €, to which the costs for the living basement were added. These were around 120 to 140 thousand euros! Oof!
In the end, both offers were at least 420 thousand, with the second offer even mentioning “the 5 in front” if certain cases occurred.

Have we so misjudged with our 300-350k € (for the house)? Does one have to say that something like this is simply not doable with the stated requirements?

Basement living on a slope is simply not cheap. A prefab house does not make things better. Whether the 4 absolutely has to be in front is something the market will tell you... 50 k€ additional construction costs, 100 k€ basement, 200 k€ house... doesn't sound so absurd at first. It also depends on your architecture / conditions.

The additional construction costs are even planned separately. 300 - 350 were initially intended only for the house + basement.

Hello everyone! Since we are planning something similar next year, I am also a bit surprised. I thought a basement apartment on a hillside would be cheaper than the living space in the upper floors. With your offers over €1,500 per sqm + €60,000? That also seems too much to me. Are there any experience reports here in the forum?

Well... thought wrong?

We have already received two initial offers, and we are still waiting for another two. In both, the basement amounted to about €60k, to which the costs for the living basement were added. These were roughly between 120 and 140 thousand euros! Uff! In the end, both offers were at least 420 thousand, with the second offer even mentioning "the 5 in front" if certain cases occurred.

Did we misjudge so much with our €300-350k (for the house)? Should one say here that such a thing is simply not feasible with the requirements mentioned?

We experienced something similar last year. The prefab house providers really dig deep into their pockets during planning. They come up with the most amazing concepts. We also had utopian plans. Also the idea of €60k for the basement plus another 2,000 euros per sqm of living space on top.

The problem is often that the basements come from subcontractors. So there is an additional interface and coordination required. Sure, when you ask, everything is easy, no problem. But when you want to know a reference project with a living basement, you only get a shrug. 95% build without a basement.

What I don’t quite understand?

"The basement should protrude somewhat to the south (towards the slope) to provide the ground floor with a small terrace."
Where then is the granny flat?

Costs are really hard to estimate. It depends a lot on the plot and how you plan the basement.

Thank you for your feedback so far!

What I don’t quite understand?

"The basement is supposed to protrude slightly to the south (towards the slope) to provide a small terrace for the ground floor."
So where is the granny flat located?

The slope is a south-facing slope and the basement is supposed to protrude slightly to the south beneath the actual house. This way, its ceiling would provide a terrace for the ground floor.
For cost reasons, however, we could also retract from this and build just a normal balcony. As I said, we are initially holding back regarding the architectural specifications. "Every corner costs money," and so does every extra... we are both aware of that. But if the whole thing can’t even be implemented “as standard,” then it doesn’t make sense :-/