Should a vapor barrier be installed in attic?

Plastic vapor barriers should only be installed in vented attics in climates with more than 8,000 heating degree days. You can forego the plastic and use a vapor retarder (kraft-faced insulation or latex ceiling paint) in all other climates except hot-humid or hot-dry climates.

Why is there no vapor barrier in the attic?

You have loose-fill insulation in the attic, which doesn’t have a vapor barrier. The theory is that part of the moisture vapor in the house is actually blocked by the drywall and paint on the ceiling.

Which way should vapor barrier face in attic?

The first layer should have the facing against the drywall to act as a vapor barrier. (The general rule for insulation is that the facing always goes toward the conditioned space.) The second layer of insulation should be unfaced so that moisture doesn’t collect between the layers.

Can you put plastic over insulation in attic?

Once you talked about stapling down sheets of plastic over rolls of insulation. In any case, a vapor barrier always faces the heated side, so it would never be put on top of batt insulation in an attic.

Is there a Vapour barrier in attic?

Houses should have a vapour barrier on the warm side of the insulation. Increased insulation means a colder attic, which in turn means that any vapour escaping into the attic can condense before it can be vented. It is essential to air seal the attic to prevent moist indoor air from getting in.

How do you fix vapor barrier in attic?

There are five options for installing an air barrier system in an unfinished attic:

1. concentrate on air sealing.
2. install polyethylene over top of the joists.
3. install polyethylene between the joists.
4. spray foam between the joists (hire a contractor)
5. spray foam under the roof to create a conditioned attic (hire a contractor)

Is it OK to use unfaced insulation in attic?

When installing between the roof rafters of finished attic spaces, you can use either faced or unfaced batting. When using insulation that has paper or plastic batting, that moisture barrier should face outward toward the attic space.

Can I use unfaced insulation in attic?

You can use either faced or unfaced batting for this installation. When using insulation that has either paper or plastic facing, that moisture barrier faces outward, toward the attic space. Even if the attic space is unheated, it typically is warmer than the outside air in winter.

Should I put plastic over insulation before drywall?

Normally interior walls do not require a vapor barrier, but there are some situations where it is highly recommended. A continuous plastic vapor barrier behind the drywall will protect the interior walls of these areas from water damage.

Can I put insulation over a vapor barrier?

When adding additional insulation to an attic that is already insulated, NEVER USE INSULATION WITH A VAPOR BARRIER!! If you do, there is a chance that moisture that has slipped by the first vapor barrier will become trapped by the second vapor barrier, decreasing the value of your insulation.

Is vapor barrier needed when insulating garage?

Most garages don’t need vapor barriers because the amount of vapor that diffuses through garage walls, ceilings, and the floor is not enough to cause wet walls that result in moisture damages. However, if you live in a cold climate zone such as Alaska, it’s a good idea to install a vapor barrier on the warm-in-winter side of the wall.

Do I need vapor barrier in the garage?

In summary, you don’t need a vapor barrier in a garage because there is not a lot of moisture in the garage. If you live in Climate Zone 7 or 8, then it’s a good idea to install a vapor barrier. You should rather pay more attention to air leakages in the garage than vapor diffusion through the walls.

Do I need a vapor barrier in my garage ceiling?

So, you don’t need a vapor barrier in the garage ceiling. Unless you have converted your garage into a kitchen, a bathroom, a laundry room, or a space that generates a lot of moisture, even for that, a dehumidifier can absorb all the moisture in the garage to keep the air dry.