What you need is an air barrier that is at every step of the way you have to pay attention to airtightness.
Thickness of vapor barrier for attic.
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.
The thickness of your vapor barrier is just one of the many considerations you need to take into account when installing a crawl space encapsulation system.
When it comes to the stairway leading into your attic you should heed the advice in this article.
A vapor barrier in an attic assembly in a severely cold climate with the absence of an air barrier will likely be ineffective.
On the other hand an air barrier a properly detailed air tight drywall ceiling for example in the absence of a vapor barrier can be effective since it stops the flow of vapor laden air.
Choosing a crawlspace vapor barrier thickness.
The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below.
It s important to choose a company that is experienced in doing this type of work and has a track record of happy customers.
The basics of air sealing are covered in this article.
Some regions don t require a vapor barrier.
Resolution of the vapor barrier debate.
Without a vapor barrier in place condensation inside the walls could ruin the insulation and promote the growth of harmful mold and bacteria.
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.
Mils is the measurement of the poly s thickness and perms represent permeability to moisture.
Avoidance of the installation of vapor barriers such as polyethylene vapor barriers foil faced batt insulation and reflective radiant barrier foil insulation on the interior of air conditioned assemblies a practice that has been linked with moldy buildings lstiburek 2002.
If you d like more information about installing a vapor.
No you don t need a vapor barrier.
Polyethylene sheeting is measured in mils a mil is equal to 0 001.
In circumstances where conditions inside a home or office are much different than outdoor conditions water.
The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it.
Some debate still occurs over how necessary vapor barriers are but a consensus is growing closer.
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.
Plastic specifically 6 mil polyethylene plastic is.
