We have a turnkey contract for our new construction, and the carpenters are currently putting up plastic after insulation. We don't know the terms or exactly how it's supposed to look. But some other friends are also building a house. There, the carpenters have taped all the seams, and I think they also let the plastic go out all the way to the windows.
This is what our interior walls look like right now... Is it supposed to look like this? Anyone know?
And in the ceiling, they've overlapped the plastic by 30 cm but haven't taped the seam. Could that be right? (However, I don't have a picture of it)
Tape the joints, pull the plastic and fold it out in the jamb, "behind" the window all the way to the outer edge of the frame.
The plastic should provide a vapor-tight layer inward, so to speak. The jamb is considered indoors and should therefore be covered with a vapor barrier.
That doesn't look quite right.
I agree with Nils82. The alcove is also a risk factor precisely because it gets colder there (closer to the outer wall), which means you absolutely don't want moist indoor air near the wooden structure.
If you don't think the craftsmen have done it correctly, you can pressure test the house after they are finished with the plastic. Don't forget to withhold payment if this is not addressed.
Here you can browse assembly instructions for different manufacturers. But no, no manufacturer believes that you should do it the way your carpenters have done... The membrane must be completely sealed. In reality, carpenters skimp on this a lot, either out of ignorance and/or because it takes quite a long time to do the job according to the instructions,
