Building with GU - Offer from GU including design

Hello,
we have received an offer from the general contractor including the draft.
Assuming the draft is faulty, e.g. roof pitch 38° instead of 45° or other "expensive" errors, and one would now sign a fixed-price contract based on the draft. Now it turns out during planning that 38° is not permitted according to the development plan. A recalculation increases the calculated price by several thousand euros.
How would that work? Does the client have to pay extra?
How is it generally handled with such deviations from the draft that are due to an error by the architect/advisor?

Hello,

Assuming the draft is faulty .......

You certainly wouldn’t do that, would you? In the worst case, it would be called fraudulent misrepresentation in court, since you were aware of the "errors".

Rhineland greetings

No, I wouldn't. But my wife would never have noticed that. And I don't know how much expertise you can expect from a client.

Always remember that YOU are the one signing the contract / order. So you cannot later say that only the GU made mistakes. It is something different if a 45-degree roof pitch was agreed upon and the GU only does 38 degrees.

Hello,

No, I wouldn't. But my wife would never have noticed that. And I don't know how much expertise one expects from a builder.

Not much, but enough that he notices if the roof is offered with 38° or 45°.

Besides, I find this question pointless. If the supplier made a wrong offer – which can definitely happen in the heat of the moment – he has to correct it. If you now signed the contract, you would have bought exactly what your signature confirmed; no more and no less. Both contracting parties are assumed by the court to be capable of checking the contents of a contract or to commission someone who can do that.

If you sign the faulty offer and later come up with your arguments from your initial post, the judge simply assumes fraudulent misrepresentation. That’s why, since you knowingly signed something different than you wanted and would later try to obtain this “forgotten” extra at unrealistic prices.

Rhenish greetings

ok, thanks. One more quick question ... shouldn't the top of the foundation slab be set at least at street level (if not even higher), so that no water from the street can run onto the property? Conversely, you have to make sure that no water can run onto the street? Unfortunately, you can't see here whether top of the terrain = top of the sidewalk: