Is a vapor barrier needed in a floor over a garage?
Tony2slow
| Posted in Green Building Techniques on
Not sure if a vapor barrier is absolutely required for the floor of a room over an unheated garage.
Reference: https://www.greenbuildingadvisor.com/question/flooring-install-vapor-barrier-or-glue
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Replies
Tony,
There are no code requirements for vapor barriers in floor assemblies. Nor are there any building scientists who recommend a vapor barrier in a floor assembly.
If you plan to install OSB or plywood subflooring, these materials will act as a vapor retarder.
In all cases, attention to airtightness is very important.
(By the way -- even though it doesn't matter in this case -- it's usually a good idea to tell us your climate zone whenever you ask a building science question.)