Is an offer binding or are deviations allowed?

Aha, and if he doesn't feel like writing me a 4th offer, then I do what? You're contradicting yourself. I should have insisted on a fourth, but good craftsmen just don’t do that, so what now?

He had to do the extra work because it wasn't clear to him beforehand that if he carries out the roof as offered, he won’t be able to make it watertight.

He didn't think of that before. Only on the construction site. And because of that, I should pay more?

Then you find another craftsman or live with the increased bill because the basis (4 offers). Many think craftsmen have to go along with every nonsense. They are simply not office professionals who master Word and only handle correspondence. They mostly do that on the side. And if they have employees, the boss has to review things again. And he doesn’t earn anything from writing another offer. You could have also rejected him after the 4th offer. Then 3 hours writing offers, 2 hours inspecting the site and holding talks. It all costs him money. He doesn’t have to deliver anything more than offered. That’s a layman’s opinion. He could have built it that way, in 6 years you’d have roof damage, and that’s it. He’s off the hook. Because carried out as offered.

That is unfortunately wrong. A craftsman must carry out the work in accordance with the Energy Saving Ordinance and aRdT. So in this case, he must build the roof so that it is airtight and no rainwater can get in.

Otherwise, I see it similarly to the majority; you should have made a fixed contract. An offer is unfortunately not binding.

That's not what it's about ... asking is the magic word ....

Help Help is currently describing the problem quite accurately ... yes I would have. In practice not possible. If you show me a single craftsman in the region here who, for example, makes the universally preached fixed price offer, I'll eat a broom (-:

Help help is just describing the problem quite accurately ... yes I would have. Not possible in practice. If you also show me a single craftsman here in the region who, for example, makes the commonly preached fixed price offer, I'll eat a broom (-:

Yes unfortunately

Did you commission any of the offers in writing? Or was the order made verbally? According to your statements, I currently see no basis for a payment exceeding approximately 32k. I would pay that amount so that you do not fall into default. Sit out the rest. Legally, the craftsman is likely to have little recourse. You should not participate in every "Dummenfang" right away.

Maybe he miscalculated. Not your problem.