Do You Need A Vapor Barrier In The Garage Attic

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 you need a vapor barrier in the garage attic.

Vapor moves in two ways by diffusion through materials and by air leakage through gaps and holes in building assemblies. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. Between the two air leakage moves far more moisture than vapor diffusion. We put the vapor retarder on the side appropriate for the season the house will be finished and then.

Here in the mixed humid climate i m in we build rotatable walls. 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. Not every wall does. A lot of people think you need a vapor barrier or class i vapor retarder and that it needs to be on the inside of the house in cold climates and outside in hot humid climates.

You don t mention whether there is a bonus room or living space above the garage. The facing on faced insulation acts as a vapor retarder. The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it. The classic answer is that the vapor barrier goes on the warm in winter side of the assembly.

Do not overlook attic access door. Hence the need to reduce moisture flow into the attic and the need for a vapor barrier. There s one other important qualification. 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. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below. Attic vapor barrier detail for cold climates 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.

Take the measurements with you when purchasing materials. Take a note of the construction of the attic and figure out which type of barrier will be suitable. To install an efficient vapor barrier you need the dimensions of the room. Measure the entire area and write down the results.

In cold climates a vapor barrier is almost always needed. In mixed climate areas the vapor barrier is optional depending on the total design of a building.