After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one.
Should attic insulation have a vapor barrier.
By compressing batt insulation you will actually lose some r value.
Within the material there is a lot of air that provides the r value and for this reason batt insulation should be loose fitting.
Not every wall does.
Most authorities now agree that vapor barriers are important under certain conditions but not necessarily as a whole house solution for every home.
Many types of blanket attic insulation already have a vapor barrier incorporated into them and will be effective at reducing moisture problems if fitted correctly.
In any case the vapor barrier must point to the warm side.
Resolution of the vapor barrier debate.
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.
Some debate still occurs over how necessary vapor barriers are but a consensus is growing closer.
Make sure that you read the instructions carefully so you know which side is the vapor barrier and how to install it.
The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below.
To stop the movement of vapor effectively through air leaks your vapor barrier should also have an air barrier such as an airtight.
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.
Batt insulation is typically made of fibreglass or mineral wool.
A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter.
Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets.
In circumstances where conditions inside a home or office are much different than outdoor conditions water.