To be able to answer this question correctly for your home there are a few factors you need to consider before any major attic insulation project.
Do i need a vapor barrier in attic insulation.
The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it.
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.
Do i need a vapor barrier.
The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below.
Take a note of the construction of the attic and figure out which type of barrier will be suitable.
Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets.
Take the measurements with you when purchasing materials.
A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter.
Whether using loose fill or batts put the vapor barrier closest to the warm side of your installation where hot moist air would get in facing the house s interior in cold climates beneath floor insulation and the attic s interior in hot climates on top of floor insulation.
Whether or not you need a vapor retarder hinges on three main factors.
Such a location works both as a vapor barrier as well as an air barrier and eliminates the need for an external air barrier not a easy application on a multi storried building as well as any special electrical pans and their sealing.
To install an efficient vapor barrier you need the dimensions of the room.
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.
Measure the entire area and write down the results.
Once thought to be essential throughout a home or office vapor barriers are now strongly recommended only for certain conditions and methods for creating a vapor barrier must be tailored to fit the climate region and type of wall construction.
If you are planning to have an attic insulation project for your home you may be wondering whether it is important to have a vapor barrier installed as well.
This barrier is meant to keep moisture from getting to the insulation in the walls and ceilings and it is required by building codes when insulating most houses.
I install my vapor barrier in the middle of the wall system between the two walls.
For example the recommended vapor barrier in a home or office in a humid southern climate built with brick varies.
In any case the vapor barrier must point to the warm side.