What is the function of the facing on insulation?
The facing material is generally a vapor retarder and is usually applied toward the “warm-in-winter” portion of the home to help resist the movement of moisture vapor to cold surfaces where it can condense. This means that in the ceilings the vapor retarder faces down; in the walls, it faces the inside; and in the floors over unheated spaces, it faces up. In hot, humid climates, a vapor retarder may not be needed. Check local building practices or building codes in your area.
