Do I Need A Vapor Barrier For Attic Insulation

In cold climates a vapor barrier is almost always needed.

Do i need a vapor barrier for 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. 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. Measure the entire area and write down the results.

If you need a vapor barrier and your insulation is unfaced you must cover it with a polyethylene film. Whether or not you need a vapor retarder hinges on three main factors. With the added insulation the attic stayed cold and so did the ventilating air from outside which was now unable to effectively remove attic moisture. This worked well until we added large quantities of attic insulation.

Do not overlook attic access door. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. Take the measurements with you when purchasing materials. 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.

Take a note of the construction of the attic and figure out which type of barrier will be suitable. Not every wall does. To install an efficient vapor barrier you need the dimensions of the room. 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.

In mixed climate areas the vapor barrier is optional depending on the total design of a building. Hence the need to reduce moisture flow into the attic and the need for a vapor barrier. I install my vapor barrier in the middle of the wall system between the two walls. 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.

A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter.