Exposed roof truss - Where is the vapor barrier?

That is anyway a lie if a roof looks from below like it is uninsulated from over forty years ago.

What exactly do you mean by that? 3-layer panels are not OSB boards and are, on the contrary, beautiful to look at ... 1000 times nicer than the usual boards you otherwise see in a visible roof truss

Here is an example

Here is an example

Exactly - this denies the fact that nowadays, pitched roofs are insulated just like the vertical exterior walls: it looks like in the time when insulation was not yet used.

Now, after the whole disaster, comes the best part...

First, an update: The manufacturer of the wood fiberboards clearly recommends a different construction method but kindly carried out the moisture calculation for us, and according to that, everything should be fine in that regard.

But now I simply have a roof that, as far as I know, only a few others would build, and I have no idea what the carpenter was thinking. And I definitely have no nail sealing tape, although it should have been used.

Whether everything fits and is airtight, unfortunately, we will only see after we have conducted the blower door test.

But now comes the best part: after all the back and forth and everything he has cost us in gray hairs (2 weeks delay because of him, as he only sent 2 people, father-in-law had to help because otherwise they would never have gotten the boards up there, then beams left too long so that the mason could no longer build 11 cm stones but only 6, for which he stuffed perlite in to fit the insulation, which he is now also charging us for).

On top of that, 2 more weeks of crane and scaffolding time for the shell builder, which he charged him for.

After all this, he sends the final invoice without a word. Plus 6,000 euros over the quotation. The main price increase comes from the fact that we chose different tiles than in the offer.

Instead of flat tiles, we chose reform tiles from the same manufacturer. These are 6 euros cheaper per square meter than the others, but instead of deducting 6 euros, he simply charged us 3 euros more... that alone is almost 3,000 euros. Additionally, items appear that were not in the offer (company delivering and installing pans).

What options do I have now? Have you had similar experiences with additional charges?

How binding is such an offer?

Have you also had such experiences with additions?

Professionally, often. Within the legal framework, you have the following options, which I would take advantage of if I were you, provided you don't still need the company:

Return the invoice by mail, with a note that the addition is not justified. You have not commissioned a change in the service at a higher price. Additional costs must be reported promptly if necessary, not only after completion.

Formally report the defect in the roof structure, if this is now one. Insist on rectification within 2 weeks. Announce a defect retention in the "amount of twice the cost of defect removal" if the deadline is not met.

Not nice how this is going.....

With other things that were actually planned, I will of course no longer commission the company, we will do it ourselves or assign it elsewhere....