A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. 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.
In any case the vapor barrier must point to the warm side. This barrier is meant to keep moisture from getting to the insulation in the walls and ceilings and it is required by building codes when insulating most houses. Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets.
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. A vapor barrier in an attic assembly in a severely cold climate with the absence of an air barrier will likely be ineffective. In this case use r 38 insulation as recommended above by energystar.
If the batts are your only layer meaning the attic joists are currently uninsulated you should install them with the vapor barrier down facing your living area below. Now with attic insulation heat is no longer lost from the living space such that moisture may remain trapped in the attic vapor barriers were therefore necessary to reduce moisture flow into the attic. The heat being lost from the house below warmed up the attic so that moisture was lost through the vents as vapor.
The attic has 2 ridge vents and 2 additional netted vents in the roof more centrally located. Newly purchased house 75 years old. Lucyna de barbaro posted in energy efficiency and durability on october 4 2015 02 12am hello i am helping family with their attic insulation in east lansing mi.
Vapor barrier in attic. Most forms of attic insulation benefit from the addition of a vapor barrier to protect them from the harmful effects of moisture which can reduce their effectiveness over time the following are a few simple steps to help you undertake the task properly so your vapor barrier retains heat without damaging the insulation. With our vapor barrier installation services there will be no issue of the crawl space of your home becoming a residence for pests bats and rodents.
Insulation labs is a name to reckon with for efficient vapor barrier installation services.
Vapor barrier for attic insulation. Attic insulation should always be installed with the paper backing facing toward the living space the ceiling in this case. This acts as a barrier to keep heated moist air from rising up into the attic during cold weather. Adding a second vapor barrier could cause condensation to become trapped in the insulation between the two vapor barriers. 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.
The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below.
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. Adding a second vapor barrier could cause condensation to become trapped in the insulation between the two vapor barriers.
This acts as a barrier to keep heated moist air from rising up into the attic during cold weather. Attic insulation should always be installed with the paper backing facing toward the living space the ceiling in this case.
