You can forego the plastic and use a vapor retarder kraft faced insulation or latex ceiling paint in all other climates except hot humid or hot dry climates.
Do i need a vapor barrier in attic.
In hot dry climates your attic can be vented though like in hot humid climates you should not install any vapor retarder or barrier.
The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it.
However all attics vented or unvented and in all climates should have an air barrier such as an airtight drywall ceiling.
Plastic vapor barriers should only be installed in vented attics in climates with more than 8 000 heating degree days.
Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic.
You have loose fill insulation in the attic which doesn t have a vapor barrier.
Not every wall does.
The theory is that part of the moisture vapor in the house is actually blocked by the drywall and paint on the.
A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter.