Do i need a vapor barrier.
Do i need attic vapor barrier in sc.
Between the two air leakage moves far more moisture than vapor diffusion.
A vapor barrier s job is to keep water vapor in humid air from diffusing through one side of a wall and finding a cool surface inside the wall.
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.
Not every wall does.
After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one.
Whether or not you need a vapor retarder hinges on three main factors.
What climate do you live in.
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.
Hence the need to reduce moisture flow into the attic and the need for a vapor barrier.
The class i vapor barriers such as 6 mil thick polyethylene sheets stop moisture migration from the bare earth into the house.
A vapor barrier reduces the movement of water vapor by.
When a vapor barrier is on the side of a wall where the dry air is i e outside in winter or inside in summer moisture problems can occur.
A plastic vapor barrier is best installed in a vented attic within climates with over 8 000 heating degree days.
Attic vapor barrier detail for cold climates.
Many people believe that it is a good idea to cover the earth with a vapor barrier even if you do meet the 1 square foot to 500 square feet requirement.
Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic.
For example the recommended vapor barrier in a home or office in a humid southern climate built with brick varies.
Even though we apply vapor barriers to exterior insulated walls in cold climates it s no longer recommended for ceilings floor of the attic.
I install my vapor barrier in the middle of the wall system between the two walls.
The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it.
Vapor moves in two ways by diffusion through materials and by air leakage through gaps and holes in building assemblies.
With a vapor barrier you will be able to significantly reduce this movement of vapor and make your living space more comfortable.
