ᐅ Connecting a vapor retarder to Ytong masonry

Hello everyone,
Can I glue the vapor barrier foil directly onto a Ytong masonry wall, or do I need to apply a smoothing layer first?

Thanks for your help.

You can do that, but it’s like trying to seal something against a chain-link fence.

Thank you for your reply.
Can I simply apply a smooth coat with tile adhesive?
Is a primer necessary or not?

Thank you in advance.