Additional floor... Liability insurance for damages?

Is it worth suing or can the craftsmen deal with it?

What do you mean by that? - below the tip of an iceberg is usually the rest as well, i.e. where there are water stains, there is also moisture inside, meaning latent damage time bombs. If the craftsmen of the construction project also carry out the repairs on the existing building, it costs extra and was not planned by the financier of the construction measure. It also does not belong to the cost center "construction measure," but is caused here by the architect's carelessness. Here, it was not the progress of the new residential unit that was damaged, but the substance of the added-on building. As the director of the overall measure, an architect cannot, like an individual participant, say he assumed that another trade would take care of it. He cannot seriously have hoped that this year rain would be exceptionally not wet. Furthermore, it must be clear to him that moisture ingress in February can also freeze, thus having "explosive power." As a professional, one must recognize the dimension of this danger, about which one cannot just casually brush over for a crate of beer.

Undisputed. But HilfeHilfe is right. You have to sue for that. And the question ALWAYS arises whether it is worth suing or not worth the effort. A years-long legal dispute with an uncertain outcome is not always the fulfillment. Especially not if, out of spite, the construction is then delayed.

I do not see only the architect liable here. Who made the roof cutout? It is absolutely normal in roof work to temporarily secure the construction site against the weather during the work. I would demand the invoices from both the roof cutter and the architect. Apart from that, one-time rain inside does not cause major consequential damage unless it was a once-in-a-century storm. It will dry, be painted, and be fine.

Aside from that, there are no major consequential damages from it raining in once, unless it was a once-in-a-century storm. It will dry, be painted, and that's it.

I also think that it can be fixed with painting work. One of the craftsmen will surely be able to fix that easily.

: How high is the damage from a financial perspective? Do you already have an estimate?