Final invoice with new (traceable) items

Primarily, the fault lies with the client/site manager due to the error in the tender.
The roofer then calculated and offered the required service.

If the roofer already knew during the tender that extra costs would arise and did not mention it, I would not pay. I know that this behavior is common practice and particularly makes public buildings expensive. Regards to the VOB. Here, the private client is supported by the Building Code, and that is a good thing.

The statement that it would always be necessary tells me that the roofer was already aware of this when submitting the price. He will bite his teeth over that.

As I said – with a good construction process, I would overlook it. With a bad one, I would not.

As I said – with a good construction process, I would overlook it. With a bad one, I wouldn't.

Yes, I would be annoyed about the extra costs, but I would understand. The problem is simply that I was lied to repeatedly and demonstrably. For example, he was almost never reachable by phone and said he always left his phone in the car. The only problem is that I saw my message was read immediately afterwards on WhatsApp. Regardless of the fact that we had many problems because of his behavior, I am now somewhat skeptical about everything. The fact that he is also insisting that I transfer the money shows me that something is wrong.