What Is A Vapour Barrier?

Vapor barrier is an important aspect of insulation. However, a lot of people don’t know what vapor barrier is, let alone its application. Here is a short paragraph that describes what vapor barrier is, and also its purpose associated with insulation. The frequently ask questions such as how to apply or use vapor barriers, where to apply vapor barrier, how to install vapor barrier and what is crawl space vapor barrier will be answered.

While you are checking the amount of insulation, another thing that you should be checking is whether there is vapor barrier associated with the insulation. A vapor barrier is a thin sheet material such as polyethylene film, aluminum foil, or an asphalt-impregnated kraft paper through which water vapor cannot readily pass.  

Many insulation materials are produced with a vapor barrier applied on one side. If the insulation does not have a vapor barrier, a separate one can be installed. The purpose of a vapor barrier is to prevent moisture problem in exterior walls and ceilings, and floors that face unheated areas, due to condensation of water vapor (normal in a house) that passes through those surfaces. To be effective, the vapor barrier must be facing the heated room rather than the cool, unheated area.