ᐅ Insulation of the top floor ceiling in new construction

Hello,

Our shell construction is now complete, and we are approaching the interior finishing phase.

I have the following question regarding the insulation of the top floor ceiling (the roof is already covered and includes an underroof plus a membrane):

The energy certificate specifies the insulation layers as follows: gypsum board - battens - vapor barrier - insulation - OSB
[IMG width="191px" alt="Energieeinsparverordnung.jpg"]https://www.hausbau-forum.de/data/attachments/67/67457-7f595f11806696267dcea9e6fa2f8519.jpg[/IMG]

After consulting with the plasterer, at least the gypsum boards should not be installed before the plaster and screed.
Can the insulation, OSB, vapor barrier, and battens already be installed? Or would it be better to only install the vapor barrier at this stage and add the rest later? Is there any risk that pushing the insulation in from above afterwards could damage the membrane (I’m a bit concerned that the membrane might tear due to the pressure from above)?

[IMG width="250px" alt="Ansicht.jpg"]https://www.hausbau-forum.de/data/attachments/67/67456-30fb502ec53cc7debdf602ff0d295fed.jpg[/IMG]

The vapor barrier is installed beneath the joists, correct? On the internet, I often see it installed in a wavy manner over the joists.

Best regards and many thanks for your answers

We installed the drywall sheets before the screed was poured; they held up well and have since dried out. I used more screws than usual, though. Otherwise, a sheet might sag or tear out, in my opinion.

I insulated from below, but the carpenters said they also do it from above, placing it on the vapor barrier. That should work, but it seemed too simple to me. 😉

I’m not familiar with any wavy installation; I wedged the insulation between the joists.