Ceiling Vapor Barrier

[ErickForest]

I have a question regarding vapor barrier in a garage ceiling. Recently moved to a different house and I want to insulate and heat the garage. The ceiling has sheetrock installed directly to the rafters. There is currently no insulation in the attic space or plastic. I'm wondering if I can place plastic over the sheetrock and then install metal liner panel over the plastic and drywall. I would have insulation blown into the attic space. I would need to install the vent shields prior to insulation. The drywall in not taped or mudded.

So I guess the question is can the plastic go over the sheetrock? The garage is located in Minnesota. Just trying to avoid removing the drywall to add a vapor barrier. The garage is attached to the house, but for only a small portion in the front right corner.

 

[The Cobbler]

that would work, a fwe coats of oil base paint is also considered acceptable to act as a vapor barrier too.

 

[TLCObsession]

Because a garage is basically very leaky, you don't need to worry too much about it but,
many PVA primers are vapor barriers. So just prime your drywall ceiling and you have addressed it.

 

[8man]

You could use spray foam insulation.