Do I Need Attic Vapor Barrier In Sc

The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it.

Do i need attic vapor barrier in sc.

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. While you are inspecting the attic check to see if there is a vapor barrier under the attic insulation. Avoid adding interior vapor barriers where the outer wall construction already includes a material with vapor barrier properties.

A plastic vapor barrier is best installed in a vented attic within climates with over 8 000 heating degree days. No you don t need a vapor retarder class i or otherwise. If you are not sure if you need insulation in your walls follow along with this flow chart. Even though we apply vapor barriers to exterior insulated walls in cold climates it s no longer recommended for ceilings floor of the attic.

If there does not appear to be a vapor barrier you might consider painting the interior ceilings with vapor barrier paint. Seal the air leakage pathways. Attic vapor barrier detail for cold climates. Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic.

If your climate does not meet these conditions a vapor retarder like latex ceiling paint will work well for your house if you are in all other climates except the hot dry and hot humid. Most authorities recommend vapor barriers in certain situations. By the time you paint the drywall though you ve brought it into the class iii vapor retarder range between 1 and 10 perms and even less water vapor will diffuse through. 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.

Your first job after the studs are in place is to fill those walls with insulation. You have loose fill insulation in the attic which doesn t have a vapor barrier. Attic insulation and vapor barrier it is not necessary to have a vapor barrier for either greenfiber natural blow in or owens propink blow in insulation except if your local building codes require it. If your current insulation is a cellulose product similar to the greenfiber natural insulation your existing 6 is equal to about a r 19.