Splice vapor barrier between ceiling and wall without stud behind?

[Gamlehav]

Should I tape the wall plastic as high up as possible with green tape? Or do I need to struggle with setting noggins behind it?

I have read Icopal and Tembalages installation instructions, and they have done as shown in the picture but they don't show how to connect the wall plastic to this. Instead, they have shown two separate cases for the ceiling and wall that do not correlate. Very frustrating.

 

[icho]

Just overlap the plastic and tape the seam. No backing supports needed.

 

[Gamlehav]

Thank you, that's what I wanted to hear