Termination of basement construction contract - experiences?

I do not deny that the mistake is on my side, but I still do not consider it too much to ask that the two parties, who each accuse the other of ignorance, have a phone call with each other. By the way, I offered him a separate payment for the phone call.

In times of Corona, video conferencing has become well established. That should still be possible today? But! As they say, "Who writes, stays." I mean to say that the meeting minutes are indispensable.

Why shouldn't the basement be officially included in the thermal envelope.

The problem here is not that the basement is not within the thermal envelope. Rather, it is that the TE only acknowledges including the boiler room from all rooms in the basement that lie within the thermal envelope in the heating load calculation!

I hope that the problems simply arise from the fact that, as a layperson, I always have to pass on information and requirements (Chinese whispers principle) and that this simply cannot work. Both are reputable companies; there must be a solution, right?

I do not deny that the fault lies with me, but I still do not think it is too much to ask for the two parties, who each accuse the other of ignorance, to at least talk on the phone. By the way, I offered him separate payment for the phone call.

You are not playing Chinese whispers here, but are ridiculously demanding too much from reputable companies if you want them to ignore the "unofficially heated" basement rooms against the proper building application. If the basement builder believes this nonsense idea came from the house provider, then of course he will throw it back at him and not you. You DO NOT have a problem, YOU ARE the problem – talk to yourself!

The problem here is not that the basement is not within the thermal envelope. Rather, it is that the TE only recognizes the boiler room from all rooms located in the basement within the thermal envelope for inclusion in the heating load calculation!

You are not playing a quiet telephone game here, but are rather demanding far too much unreasonably from reputable companies if they are supposed to ignore the "unofficially heated" basement rooms in your imagination against the proper building application. If the basement builder thinks this nonsense idea came from the house provider, then of course he will throw it at them and not at you. You do NOT have a problem, YOU ARE the problem – talk to yourself!

Now, now, that’s starting to get rather rude!
The house is absolutely properly thermally separated from the basement. It is not unusual and is also in compliance with the Energy Saving Ordinance to have the heating insulated in the basement.
The basement will receive a U-value under 0.35 according to the component proof for low-heated rooms (12 to 19 degrees). It is also completely fine to install an infrared heater or a surface radiator connected to the air heat pump later in the rarely used hobby basement—that will be technically clarified in due time.
Buying a house and having the basement separate is also not unusual. With prefabricated houses, one usually does not commission a separate architect; that is all included in the services for the basement. The house builder also calculates €3000 for the additional costs of considering the basement.
I maintain that it is quite sensible if the two companies communicate directly with each other once and then determine what I, as the builder, may still need to commission additionally.

Well, if you are so sure about that and everything is in order, then: Good luck! I am however surprised why you opened this topic then.

Well, if you are so sure and everything is in order, then: Good luck! But it does surprise me why you opened this topic then.

My topic was whether anyone has experience with the termination/cancellation of a basement contract!

My topic was whether anyone has experience with the termination/cancellation of a basement contract!

A legal consultation on this (initial consultation) will not cost you 200€. Then you will know if the flat fee claim of 8% is generally legally compliant or if the expenses due to a termination must/may be determined differently. When is the planned start of the basement construction? The closer the date, the more likely it is that materials have already been ordered and thus 8% as compensation is no longer sufficient. You can theoretically terminate almost any contract, according to the agreed or legally/highest court established conditions.