The vapor retarder shall be installed on the warm-in-winter side of the thermal insulation.” A lot of people call this a “vapor barrier” requirement, and believe polyethylene is required by the code, but kraft facing on batt insulation (which has a permeance of about 0.4) meets this code requirement all by itself.

Do you need Poly with faced insulation?

The vapor retarder shall be installed on the warm-in-winter side of the thermal insulation.” A lot of people call this a “vapor barrier” requirement, and believe polyethylene is required by the code, but kraft facing on batt insulation (which has a permeance of about 0.4) meets this code requirement all by itself.

When should you use faced insulation?

Faced, or the type with paper, is typically used in first-time applications, such as in walls, ceilings, floors, and in crawl spaces. Any time you use a faced insulation, the paper needs to be facing toward the living space. So in an attic the paper faces downward and in a crawl space, it faces upward.