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

It's a ridiculous situation. Why have you already sold your condo? If the legal advice says it's watertight, I would first approach the construction company. What kind of place is that?

According to our financial advisor, we had to sell the apartment, otherwise we wouldn't have gotten a loan or only at a high interest rate.

It's a small regional construction company for solid construction.

Prices are valid until xx.xx, for later order placement we reserve the right to adjust prices. To place the order, please send us a copy of the signed order back“ And that is what we did then.

What was stated instead of xx.xx in the letter you already signed?

And, then I can only support once again .. you also mentioned something about 2xKfW funding in the other thread, because of a granny flat? That was you, wasn’t it? So the plans would be important. Has the KfW funding already been approved? So the approval took place before 01/24?

I understand: nothing. And I’m afraid I’m not alone here. An offer is signed by the provider. If you as customers have also signed it, then you have not an offer, but its acceptance signed – in other words, you have concluded a contract. You can no longer "cancel" it, only terminate it. If it contains nothing about the consequences of termination, you will probably have to derive the answers from the Building Code (or rather: painfully here). From your talk of a "final contract" that would still be in the future, I gather that the contract has not yet regulated essential points. The "extended shell" probably refers to a kind of shell-and-core stage, i.e., for example, that the contractor is supposed to build you a house with a tight roof, windows, and exterior plaster, after which he can pack up his tools and you are left to your own devices. This all sounds very much like being adrift on a pedal boat in distress. A pity about the sold condominium, at least that was finished. You should tell more about the house: from the mentioned floor area I derive about 68 sqm of living space on the ground floor, as a one-and-a-half-story house about 102. Replacing speculation here with a factual basis could be helpful ;-)

what was stated instead of xx.xx in the letter that you have already signed?

And, then I can only support once again .. you also wrote something about 2x KfW funding in the other thread, because of the granny flat? That was you - right? So the plans would be important. The KfW funding has already been approved? So the approval took place before 01/24?

The prices were binding until 03/03.

Sorry, I completely forgot that here. A small granny flat is planned in the basement, we are receiving 2x the funding for KfW 55. This was already approved for us in November 2021.

I understand: nothing. And I’m afraid I am not alone here. An offer is signed by the provider. If you as customers have also signed it, then you have signed not an offer, but its acceptance – so you have concluded a contract. You can no longer “cancel” it, only terminate it. If it contains nothing about the consequences of termination, you will probably (or rather: unfortunately) have to derive the answers from the building code. From your talk of a “final contract” that would still lie in the future, I understand that the contract has not yet regulated essential points. The “expanded shell” probably means a kind of shell stage, for example that the contractor should build you a house with a tight roof and windows and exterior plaster, then pack up their tools and you have to seek your further luck alone. That all sounds a lot like a pedal boat in distress. A pity about the sold condominium, at least that was finished. You should tell us more about the house: from the mentioned footprint I derive about 68 sqm living space on the ground floor, as one-and-a-half floors about 102. Replacing speculation here with a factual basis could be helpful ;-)

Sorry, I really don’t know anything about this. We just received an offer and we signed it. So it is as you say, we signed the acceptance. It is clear that we can’t just cancel; we would have to ask for a termination agreement and probably pay a contractual penalty.

This is not a prefabricated house or a large home builder, but a small regional company that builds solid houses. Their statement was that they only offer us the expanded shell phase firmly because they can define the prices here. And when the time comes, we will discuss the current prices for electrics, heating, and co...

I am happy to upload the plans.

Here are the requested plans. The garage was already planned as a prefabricated garage.