First alleged fixed price and now additional costs - legal?

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then you can plead incapacity to contract, can't you?

How should that be proven or explained?

How should that be proven or explained?

A doctor must determine the incapacity to conduct business.

That can happen to you with any other contractor just the same. As a builder, you have to inform yourself. Building is a business. It’s not for amateurs.

I can only emphasize that, from the feeling, I would say that I got the maximum out of my house... I’m in my mid-30s, do sports, can stand up for myself, and have a large/many family/friends who would support me if it escalates.... During the construction period I had some craftsmen who even threatened me with violence, I am a direct and open person where I questioned some invoices, for example... that caused problems for one or the other. I never gave up and always kept my composure, at the same time I looked for a solution. I’m not Superman, but you have to put a lot of energy into certain moments... but there are enough people who are cold-hearted and only out to cheat. Some people are simply no longer able to defend themselves against such things, and it doesn't help if someone falls into a hole and you tell that person "You shouldn’t have fallen in, because now you can’t get out anymore." The approach from is good! Try to keep it short..... Good luck!

If it already starts like this now, please leave it and pay the 10%.

I think much more is coming!

Perhaps this is still a legal possibility. Probably not, though.

You suspect correctly. Signed means = contract accepted with change.

Just google “Termination of construction contract possible without 10% contractual penalty?” A specialist lawyer states that everything is lawful and let's be honest, the OP is not able to disprove that no material and personnel costs of that amount have been incurred by the general contractor. Anyway, the issue is settled. According to the lawyer, the OP will not get out of it without compensation.

Here you have the lawyer, you just have to do what you are advised. By the way, I have asked several times what is in the payment plan and what has already been executed.