Unpredictability of construction costs - Will the project fail because of it?

How were the costs calculated that come after the shell construction? Do you also have an "offer" for that? You must have gone to the bank with something to fix the amount of your loan. I would definitely get legal advice on that. Do you even have a valid contract now? Can the contractor still completely back out on you? That should actually be clear before signing the financing. This needs to be clarified as quickly as possible now.

can you leave out controlled residential ventilation? What does the energy consultant say?

I would change the floor plan again. Where is the garden access? The mini granny flat is actually not for rent. And does one want that? Gather your documents and get advice from a lawyer. Do you have a contract now or not? Is the price allowed to be increased, etc.?

I would change the floor plan again. Where is the garden access? The mini granny flat is actually not meant to be rented out. And is that what you want? Gather your documents and get advice from a lawyer. Do you have a contract now or not? Can the price be increased, etc.

It just costs time and money. Besides, the bank has to cooperate as well. I also think that anyone at this stage of the project no longer needs floor plan advice. In my opinion, it doesn’t help anymore. It only causes unnecessary uncertainty.

Where can you actually get a garage for €20k?

At Zapf. Double garage with two doors.

How were the costs calculated that come after the shell construction? Do you also have an "offer" for that? You must have gone to the bank with something to fix the amount of your loan. I would definitely get legal advice on that. Do you even have a valid contract now? Can the contractor still back out completely? That should actually be clear before signing the financing. This needs to be clarified as soon as possible.

I can gladly upload the offer later. As we had signed the offer, the contract was binding and neither they nor we are allowed to just back out.