GU demands a price increase on the entire house

Hello everyone, I have already read a lot and hope for a little help... We are building a house and are 90% finished. The price lock expires at the end of October and contractually nothing is regulated about what happens afterward. Now our general contractor came up with a demand for €50,000. His justification: as of today, the house is 18.66% more expensive, meaning €51,250, so he is demanding €50,000 from us. He already indicated on the phone that it wouldn't be €50K, but the offered €10K from us was too little. Now the question is whether we are seeing this completely wrong? I don't see why we should pay more for the whole house but only for the items that are still open. That's about €8K if you really take the 18%. Do you understand what I mean? Does anyone have legal knowledge or a few tips on how to argue here? Our lawyer advises a settlement in the range of €15-20K.

What is stated in the contract (exact wording)?

What does the contract state (wording)?

The contractor is bound to the flat rate mentioned in No. 1.) for a period of 12 months from the conclusion of the contract.

Hi,
um, the price binding should generally refer to the start of construction. In other words, when the [GU] begins, they have to complete the house within period X at a price of Y. If they delay the construction, they have to pay a penalty and not charge additional costs. With the [GU]’s argument, they could also delay attaching the doorbell for 10 years and then demand the house price from you in 10 years. (Yes, this is exaggerated, but that’s what it boils down to.)

But the contract structure must be very strange, you apparently already went to a lawyer and even he advised you to pay 15-20 k€?!?

Maybe you can provide a bit more information, it doesn’t all add up like this.

Best regards,

Andreas

From when is the contract and how does the GU come to the conclusion that it is now 51....€? Own calculations or construction cost index? Was the GU obliged to any preliminary services (e.g. building application...) that may have caused delays? What is stated about the construction period?

Hi,

The contractor is bound to the flat rate price specified in No. 1.) for a period of 12 months from the conclusion of the contract.

There needs to be more stated. Something like this is usually meant (and presumably understood by you) that he must start construction within 12 months and at a price of X. That does not mean he is rewarded for slowness.
Why does the lawyer advise you to pay?

Best regards,
Andreas