ᐅ We are planning our house construction and are currently working on the cost estimation.

Good morning,
we are a family with one child and are planning to build a house.
The house is planned to be built on the property of the parents-in-law. However, there is an old barn on the site that needs to be demolished. We have already received quotes for this. The demolition would cost about 20,000 EUR.

Now our question is what costs we should expect for the house itself, as well as for site development and additional fees.
We are planning a single-family house with solid construction, approximately 130–140 sqm (1400–1500 sq ft) and 5 rooms, without a basement. The house will have a staggered shed roof.
We have an appointment with the bank soon to discuss financing. For this meeting, we would like to have at least a rough estimate.

Thank you very much.

A rough estimate of the cost for something like this can be given by a construction company once you have shared your requirements with them. Your information is still quite limited.

Very approximately, I would start with a price of at least €1600 per m² (approximately $175 per sq ft) for a "turnkey" build.

Thank you very much for your reply.

What additional information is still needed? I will provide it as best as I can.
Does the 1600 EUR per square meter include additional costs, or would those be added on top?

The typical additional construction costs, of course, also need to be considered.

Factors that greatly affect the price include things like KFW55/40/40+ standards; centralized controlled residential ventilation systems; electric shutters; the level of requirements for electrical wiring, LAN, and satellite systems; garage or double garage, and so on.

It should be a KFW 55 house.
We would like to have an air-to-water heat pump for heating.
Electronic roller shutters should also be installed.
A LAN cable does not need to be laid in every room. The same applies to the satellite connection—only the living room and children's room.
A carport would be nice but is not strictly necessary.

Then you will probably not manage with €1600 per m² (approximately $160 per sq ft). But all of this is just guesswork.

Visit 1-2 construction companies, create a rough plan including a cost estimate, add about 10% to that, and you will have a general idea of where you will end up.