The roof structure rises by almost 2 cm upwards!

Hello truce, thank you very much for your reply and the tip about the images As you can see above, this is already very serious........:-(

OSB boards can indeed expand. Have you installed them with expansion joints?

Yes, I already know that OSB boards expand, so I should leave space on all four sides, for example to the gable, etc. ... However, nobody mentioned that they expand upwards and cause cracks of 2 cm in the upper floor :-(

So, on the large crossbeams we practically screwed on small wooden slats again, about 2.5 meters long and about 5 cm wide; then we screwed the OSB boards onto these slats.

The cracks are really quite large already.

Can you say something about the process?
At what temperatures was the upper floor built, when was it painted?
Was it already heated at that time?

Roof truss is made of KVH? Wooden battening under the drywall?

Just so you know: it is normal for the ceiling upstairs, meaning the drywall, to separate from the wall. ... Therefore, if the painting work is done in EL, you will eventually have to apply acrylic. Should it really be the roof structure? [emoji15]