So you don t need a vapor barrier in the garage ceiling.
Vapor barrier in garage ceiling.
Install as directed typically cutting to fit and using a staple gun to attach the vapor barrier to the studs.
Water vapor can pass through building materials in several ways including direct transmission and by heat transfer but studies suggest that fully 98 percent of the moisture transfer through walls occurs through air gaps including cracks around electrical fixtures and outlets and gaps along baseboards.
If you re using old uninsulated doors pick up a retrofit kit that add insulating panels.
The science of moisture movement.
It s also incorrect in a way.
Not every wall does.
First of all a garage is not a signicant source of vapor as it is not occupied that much and you don t cook or bath in in it.
After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one.
Omitting a ceiling vapor barrier by arguing that you have to let the moisture escape or because the house has to breathe out the top is actually correct in a way.
A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter.
And the ceiling acts as a enough of a vapor retarder.
Thus installing vapor barriers on wall surfaces must.