Seal the air leakage pathways.
Do i need a vapor barrier in my garage attic.
However all attics vented or unvented and in all climates should have an air barrier such as an airtight drywall ceiling.
The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below.
In hot dry climates your attic can be vented though like in hot humid climates you should not install any vapor retarder or barrier.
Here s what you need to know about the facing on attic insulation.
My other consideration would be insulating the exterior walls.
A vapor barrier in an attic assembly in a severely cold climate with the absence of an air barrier will likely be ineffective.
This makes it absolutely necessary to have a good vapor barrier and good venting to avoid potential interior rain storms lol.
A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter.
Not every wall does.
The facing on faced insulation acts as a vapor retarder.
After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one.
Since there seems to be only one long wall and very little framed cavity wall on the gable ends it would be advantageous to go ahead and finish the job by insulating and drywalling these walls.
No you don t need a vapor retarder class i or otherwise.
By the time you paint the drywall though you ve brought it into the class iii vapor retarder range between 1 and 10 perms and even less water vapor will diffuse through.
If you need a vapor barrier and your insulation is unfaced you must cover it with a polyethylene film.
Do not add a vapor barrier on top of the insulation in your attic since the paper facing on the existing insulation is the vapor barrier.
In mixed climate areas the vapor barrier is optional depending on the total design of a building.
The best approach for a vented attic in a cold climate is installing a layer of drywall with a good coat of latex paint the paint creates a semi permeable vapor barrier.
It s important to use the right type of insulation to prevent moisture problems in your attic.
Attic insulation is available with and without a paper facing.
The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it.
In cold climates a vapor barrier is almost always needed.
