Garage Attic Insulation Vapor Barrier

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.

Garage attic insulation vapor barrier.

The classic answer is that the vapor barrier goes on the warm in winter side of the assembly. If you need a vapor barrier and your insulation is unfaced you must cover it with a polyethylene film. You don t mention whether there is a bonus room or living space above the garage. If your garage is 45 degrees and you have a bonus room heated to 72 degrees above the garage the vapor retarder faces the upstairs room.

In mixed climate areas the vapor barrier is optional depending on the total design of a building. The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below. Attic insulation should always be installed with the paper backing facing toward the living space the ceiling in this case. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one.

Not every wall does. Adding a second vapor barrier could cause condensation to become trapped in the insulation between the two vapor barriers. If you are not sure if you need insulation in your walls follow along with this flow chart. The facing on faced insulation acts as a vapor retarder.

In cold climates a vapor barrier is almost always needed.