Is cost calculation for a prefabricated house feasible? Are there additional costs?

Hello first of all as a newcomer here,

I’ll keep it brief:
we are about to buy an old house cheaply with the intention to have it demolished and to have one semi-detached house as a prefabricated house built on it with my brother. However, the land costs are waived since we are sponsored at the corner by our parents. We only need to finance the house.

We have looked at some prefabricated house providers and we like a semi-detached house from Drevo.
Catalog price 250K turnkey - divided by 2 families it would be
125K costs per family.
+ 35,000 extras
+ 45,000 basement?
+ 5,000 garage?
+ 50,000 ancillary construction costs? (What is actually always calculated there?)
+ .....?????

Am I totally wrong or can someone tell me how it could rather be?

I am grateful for any advice and help!!!!!

What does the catalog price mean here? What is included in the offer, what is not? What does turn-key mean here?

Prefabricated houses are offered from the top of the foundation slab, so additional costs arise here. Then you calculate with 1800/2000€ per square meter. Everything that is missing in the 125,000 here comes afterwards, because it is not included in the construction service description, on top of that. Somehow you always end up at the sqm/estimate price (according to the experience of some users here). Are qualitatively good materials used or cheap goods that have to be upgraded expensively? How expensive are the extras, which extras do you want?

By the way, prefabricated houses are somewhat more expensive than solid houses. Not much, but it seems to me that you seem to be looking more at a cheap product than a mid-priced one?

For the question about additional construction costs, just have a look here in the forum, the topic is addressed on every page.

Is it even allowed to build a duplex house there? That is, a house with two residential units?

Regards

which size ?

I quickly checked on Drevo's website, regarding the semi-detached houses the price is understood to be per semi-detached house half!

Their search spits out a semi-detached house "from 108k". Do you mean that? That's the only thing that fits into your price range. But you have to consider that they have different levels of development.

No, it is the 186 SD