Paper or plastic in exterior walls?

[Suhagg]

What is preferred and what is best?
Paper in outer walls and plastic in the ceiling have been recommended to me.

 

[hakaner]

What do you mean, outermost or innermost in the wall/ceiling?
More detailed: As diffusion barrier/vapor brake or wind protection for blowing in insulation?

 

[andersmc]

Cardboard and plastic have completely different purposes and are not something you can choose between. The cardboard is usually placed outside the insulation to prevent wind from blowing into it. The plastic is on the inside to prevent condensation in the insulation. If you choose to use plastic, it is pointless to place it here and there. It must be fully covering and completely sealed.