Construction cost breakdown plausible?

Hello everyone,

we are currently planning the construction of a single-family house in southern BW. As of today, it is supposed to be a prefab house from the big W. So far, we have received a first non-negotiable offer for the house (individually planned) including the basement. Here are the details of the house: 160m² living space + basement, two stories, hip roof 22°. The house is to be handed over finished except for floor coverings and painting work. Currently, a ventilation system with heat exchanger is planned as heating.

I have created a table from various forums and blogs with the costs that we will probably face during the construction and would like to get your feedback on how accurate these cost assumptions are. The plot of land is already available, but not yet developed. The connections are located in the adjacent street.

House including basement: €326,000
Painting work: €13,000
Floor coverings: €10,000
Architect: €10,000
Structural engineering: €1,500
Soil survey: €1,000
Building application: €1,000
Surveying: €2,000
Civil engineering: €20,000
Development: €10,000
Connections for basic supply, land registry office, KfW calculation: €8,000
Double garage (construction site, own work): €20,000
Miscellaneous (buffer, some outdoor facilities, tools, etc.): €25,000

Have I forgotten anything essential here?
As I said, except for the costs for the house, I have no concrete offers yet. The other numbers have been compiled from various forums and blogs and possibly rounded up.

Best regards
Torsten

Does the structural engineer and the architect have to be paid extra for the large W prefab house? Is there a soil report for the property? Edit: I just read that the report apparently is still pending.

The costs for the architect still need to be clarified, since we want a custom house, I suspect the costs will start. There is no soil survey yet, the basement is currently planned as a [Weise Wanne] because we will be building near a river.

Question about the architecture.

Is your house rectangular or are there projections, bay windows, etc.?

There is a projection and a covered terrace at the corner, which serves as a balcony on the 1st floor. Why do you ask?

An air-to-air heat pump? Do some more precise research to see if that is really what you want. It is the cheapest type of heating in terms of investment costs – the operating costs might possibly not be that cheap. Additionally, you have to run high air exchange rates, which makes the air very dry and you might also get dust combustion. Another provider, the one with the K, no longer offers such cheap solutions and even with their significantly better insulated building envelope relies on a water-based surface heating system (=underfloor heating).

You should be able to calculate floor coverings yourself based on what you want.