Price increase - Our construction company wants 21.4% more

The GU doesn't start with K... does it?

Kampa?

Yes.

In which town is the GU K....... located?

Aalen?

GU with K....

Kampa?

By now 21.4% higher for their construction project.

Someone asked if the increase applies only to a part, e.g. the roof. ?
I clearly read this as an overall increase, so 21.4% on everything.

Was it not contractually regulated how price increases may be handled after the fixed price commitment?

I fear, however, that you have no legal recourse against this price increase.

Or where is the flaw in the reasoning?

With the force majeure that the GU refers to.

Not Kampa. GU was recently described positively in the moderated subforum.

Kampa?

No. I don’t think there is much left now.

As far as I know, Corona cannot be counted as "force majeure" 1.5 years after the beginning. At least not categorically.

Not Kampa. GU was recently positively described in the moderated subforum.

Keitel-Haus?

No. I think there isn’t much left now.

It must be insanely funny and entertaining to let someone guess something here when you know it yourself :D

As far as I know, Corona can no longer be considered "force majeure" 1.5 years after its onset. At least not universally.

He did not write Corona in the letter, but that his contractual partners terminated the contracts/conditions with him. Something like that. Please read it yourself.
Here:

For some products, previously agreed conditions have been terminated in the meantime. They refer to "Force Majeure" / higher force here.