Neighbor is building a house next to the garage, neighbor's wall is wet

Did you meet on the roof in the rain?

How do you come to that? Currently, these are claims on his part. I am now trying to find out whether there could be something to it.

Such amateur stuff is not helpful. One must determine whether it is really (measurably) wet and then a professional must take care of it (also a roofer or something). A meeting with the estranged neighbor on the garage roof in the rain? What is that supposed to achieve?

Thank you!

Such damages are occasionally seen where both components belong to the same owner. For the initial diagnosis, a roofer is sent out, which is usually sufficient. Common causes are a leaking seal and a clogged drain. Both parties could initially share the roofer amicably; perhaps that alone is enough.

I would not advance payment with a specialist; I think it is too early. The other party wants something and can therefore initially cover the costs themselves, especially since a court would follow their newly commissioned neutral expert.

It is certainly advantageous if the "accused" signals that he/she will of course comply with an undisputed obligation.

The dew point is more important than it initially sounds. It is enough if the affected room is too cold; nothing else has to be broken.

Best regards
Gabriele

Layman stuff is not helpful

Then he doesn’t need to ask here at all, there might be 1-2 experts who write something once in a blue moon. What he can get for free, however, are experience reports.

And when I look at the sheet metal like that and the gaps underneath, my question is justified.

Better a fire in the house than a leaking roof.