ᐅ Roof truss rises by almost 2 cm!

Created on: 26 Feb 2018 19:04
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ChristopherST
Hello

I have a question about who is responsible for the costs. I started building my house in September 2016 and successfully completed it in October 2017. The house is single-story. My problem is that I have very large cracks between the walls and ceiling on the upper floor. They are almost 2 cm (0.8 inches) wide. The upper floor does not have a concrete ceiling; it only has drywall. Last summer, I installed OSB boards on the attic floor and screwed them onto the roof beams. According to the construction company, I should only leave space for ventilation at the sides and the gable. I followed these instructions. However, the site manager now tells me that the cracks were caused because the OSB boards expanded and, since they are screwed in, pushed the entire roof structure upward. Fixing this would cost me about 1000 euros.

About a week ago, I removed all the screws from the boards on the attic floor. The site manager said the roof structure would lower again, but so far nothing has happened. The cracks are at the top of every room. I screwed the OSB boards onto the attic floor in July of last year, and the cracks appeared in November.

Is it really possible that the OSB boards could push the entire roof structure upward by almost 2 cm (0.8 inches)? I would be very grateful for any advice, as I don’t really understand this issue.

P.S. If pictures are needed, I can provide them without any problem.

Thanks in advance.

Best regards
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ChristopherST
26 Feb 2018 20:02
Narrow crack edge at the joint between the gray area above and the white, textured wall below


White ceiling with a small rectangular cutout/panel near the wall
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ChristopherST
26 Feb 2018 20:03
Hello truce, thank you very much for your reply and the tip about the pictures. As you can see above, it is already quite serious........:-(
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Baumfachmann
26 Feb 2018 23:50
OSB panels can indeed expand.
Did you install them with expansion joints?
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ChristopherST
27 Feb 2018 04:41
Yes, I am already aware that OSB panels expand, which is why I planned to leave gaps on all four sides, including near the gable, etc. However, nobody mentioned that they would expand upwards and cause cracks of 2 cm (0.8 inches) on the upper floor :-(

So, on the large cross beams, we basically screwed on small wooden battens about 2.5 meters (8 feet) long and approximately 5 cm (2 inches) wide. The OSB panels were then screwed onto these battens.
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kkk272729
27 Feb 2018 07:19
The cracks are already quite large.

Can you provide some information about the process?
At what temperatures was the upper floor constructed, and when was it painted?
Was the building already heated at that time?

Is the roof structure made of kiln-dried structural timber (KVH)? Is there wooden battens under the drywall?
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ypg
27 Feb 2018 12:35
Just as a side note: it is normal for the ceiling drywall on the upper floor to separate from the wall. ...
That’s why, if the painting work is done in the final phase, you will eventually have to apply acrylic sealant.

Is the roof structure really the issue? [emoji15]