Faced insulation refers to insulation that has a vapor barrier or a vapor retarder, such as kraft paper, foil kraft paper, aluminum foil, or vinyl, attached to it. The facing helps protect the surface, hold the insulation together, and fasten the material to building components. It also helps prevent moisture from moving from one space to another and provides a moisture barrier that keeps water from being absorbed by the wall or into the rest of the home.

Unfaced insulation, on the other hand, lacks a vapor retarder or paper or plastic facing. It is great for new construction, remodels, walls, floors, ceilings, basements, attics, and crawlspaces. It is best used for interior wall applications that do not face the outside and also in rooms that don’t need moisture control, like living rooms, dining rooms, and studies. Unfaced insulation should fit snugly into the space but shouldn’t be compressed.

The choice between faced and unfaced insulation depends on the specific needs of the project. Here are some guidelines:

When to use faced insulation:

• In cathedral ceilings (foil-faced batts are often used in these types of ceilings for the permeability rating frequently required for use in ceilings without attics)
• In spaces that require insulation with a fire rating (some facings provide flame resistance)
• When downward heat flow needs to be prevented (radiant barriers, which have facing, are effective at doing this)

When to use unfaced insulation:

• When adding new insulation over existing insulation
• Depending on the material, anytime a facing isn’t required (for instance, spray foam may be ideal for the walls and facing isn’t necessary)

It is important to note that state guidelines may require a specific type of insulation, such as paper-faced insulation, which provides a moisture barrier. In such cases, other types of insulation may not be allowed or may require professional installation.