The roof structure rises by almost 2 cm upwards!

Hello

This is about the question of who is responsible for the costs. I started building the house in September 2016 and successfully completed it in October 2017. The house is one-story. My problem is that I have very large cracks between the wall and the ceiling on the upper floor. Almost 2 cm wide. There is no concrete ceiling on the upper floor, only drywall. In the summer, I installed OSB boards in the attic and screwed them onto the roof beams. According to the construction company, I should only leave space to "let it breathe" on the sides and at the gable. I did exactly that. But now the site manager tells me that the cracks were caused because the OSB boards expanded and that because they are screwed in, they pushed the entire roof structure upwards, and that it would cost me about 1000 Euros to fix it. A week ago, I unscrewed all the screws from the boards, the site manager said it would settle again, but nothing has happened yet. The cracks are at the top in every room. I screwed the OSB boards onto the attic in July last year, and the cracks appeared in November. Is it really possible that the boards pushed an entire roof structure upwards by almost 2 cm? I would be very grateful for any answers since I really don’t know much about this.

P.S. If I should take pictures, that would be no problem

Thank you very much in advance.

Best regards

Don't let anyone pull the wool over your eyes. Why should the OSB boards expand? And if they do, how are they supposed to lift the roof truss structure?

Because of the temperature fluctuations, since it is very cold in the attic now and warm on the upper floor, and because the panels are screwed down, they cannot expand sideways and therefore expand upwards. The roof structure is not insulated, it is already very cold up there but I had a carpenter look at it again two days ago, he helped me with this before, he said he has never experienced anything like what the site manager is telling me...... That's why I wanted to ask now if this can really be the case :-( .............. I would have uploaded a photo now, but it gives me an error message "The file is too large" .....

Sorry, but that is such nonsense. Where should one even start? I would send a written notice of defects with a deadline for rectification by registered mail. If you are unsure about the correct form, get help from a lawyer or expert.

Ok, many thanks for your quick help, then I will go in that direction..........Because it also seems a bit strange to me that such thin OSB boards pull an entire roof structure including the cross beams up into the attic........

Because of the temperature fluctuations, since it is very cold in the attic now and warm on the upper floor and because the panels are screwed in, they cannot expand sideways and therefore expand upwards. The roof frame is not insulated, it is already very cold up there.

Rarely heard such nonsense. OSB panels are real all-rounders and can do a lot – but lift a roof frame?? Hahaha.