The managing director of the contracted construction company said that due to the structural engineering, massive walls instead of drywall now had to be built in the attic. He initially estimated the additional costs at just under €1000, two days later it was €3,802 because he had forgotten a beam in the first calculation. In addition, there was a change in the attic space deemed necessary by him, with approximately €1400 in additional costs. I then informed him that we were not willing to bear these additional costs, as the changes were not requests from the clients and the structural engineering had been calculated by an architect commissioned by him.
Have you even read the construction contract?
It doesn't seem so.
To quote from your construction service description:
"Additional costs that become apparent only after the structural analysis and execution planning due to structural or energetic reasons are not included in the fixed price."
This clause can be found in almost any construction service description. The general contractor usually calculates with a certain amount of reinforcing steel or concrete. If that is not sufficient, the client has to pay the rest. How could it be any different? The general contractor is normally not a clairvoyant and does not know to the kilogram how much reinforcing steel needs to be installed without structural calculation.
Honestly, the general contractor really seems to be an idiot, but if you make demands that are clearly not covered by the construction service description, then in my view you are already partially to blame if the general contractor digs in his heels.
