Vapor barrier - which material is best...?

[sepani]

Hi, we are going to replace the insulation in the attic of our 70s house. Today, there is a vapor barrier that is partly damaged in many places and partly very "thin," like the plastic bags used to buy fruit in the past... Now we are tearing out all the insulation, and I thought I would take the opportunity to replace the vapor barrier. What material is best? Age-resistant plastic? which is quite "thick".

 

[larsbj]

It should be aging-resistant plastic, diffusion-tight/vapor barrier. It should be placed close to the inside of the construction.

Alternatively, a vapor retarder can be used, breathes a little more.

 

[sepani]

It should be aging-resistant plastic, diffusion-tight/vapor barrier. It should be placed close to the interior of the construction.

Alternatively, a vapor retarder can be used, breathes a bit more.

Thank you! I thought it shouldn't breathe at all? hence "thick" aging-resistant plastic?