Is kraft facing a vapor barrier?

Usually no. In most assemblies it is treated as a vapor retarder, which slows moisture movement but does not block it completely. That distinction matters because the correct insulation detail depends on climate and wall design.

Which side should kraft-facing face?

In a typical heating climate, it faces the conditioned interior side of the assembly. The right orientation can change in mixed or hot-humid climates, so if you are unsure, follow the local energy code or insulation manufacturer's guidance instead of guessing.

Can torn kraft-facing be taped or repaired?

Small tears can sometimes be patched, but widespread damage usually means the batt was handled poorly or got wet. If the facing no longer lies flat or the cavity has moisture issues, replacement is the safer fix.

Can kraft-faced insulation be left exposed?

Normally no in occupied areas. The facing is combustible, so it usually needs to be covered by drywall or another approved thermal barrier once the insulation is installed.

Kraft Facing — Fiberglass Batt Vapor Retarder Guide

Kraft facing is the asphalt-coated kraft paper vapor retarder attached to one side of some fiberglass batt insulation.

Kraft Facing diagram — labeled parts, dimensions, and installation context

What It Is

Kraft facing is the brown paper layer stapled or friction-fit toward the conditioned side of a wall, floor, or ceiling assembly when faced fiberglass batts are installed. It is not the insulation itself; it is the facing attached to the insulation to help slow moisture movement and make installation easier.

In most homes, kraft facing functions as a Class II vapor retarder rather than a true vapor barrier. It helps control moisture diffusion through the assembly, but it can still be damaged by tearing, bad stapling, compression, or installation in the wrong climate zone or orientation.

Types

The most common type is standard asphalt-coated kraft paper attached to fiberglass batts for walls, floors, and ceilings. Some batts use foil facing instead, and unfaced batts have no vapor-retarding layer at all.

Kraft-faced batts may be designed for inset stapling or face stapling depending on the cavity and installer preference. The paper flap layout changes, but the core purpose of the facing stays the same.

Where It Is Used

Kraft facing is used on fiberglass batt insulation in exterior walls, basement walls, floor cavities over crawl spaces, and some sloped ceilings where the assembly calls for a vapor retarder on the warm-in-winter side. It is common in unfinished basements, garages, attics, and open stud cavities during construction or remodeling.

Its correct placement depends on climate and assembly design. In the wrong location, or when combined with another low-perm layer, it can trap moisture instead of helping manage it.

How to Identify One

Kraft facing appears as brown paper attached to one face of a fiberglass batt, often with stapling flanges along the edges. Printed installation instructions or R-value markings may appear on the paper surface.

Torn paper, mold staining, detached flanges, or batts installed backward are common signs of poor installation. Kraft facing should not be left exposed in occupied spaces because the paper is combustible and usually must be covered by drywall or another approved finish.

Replacement

Replacement is needed when the facing is badly torn, wet, moldy, pest-damaged, or installed in a way that traps moisture in the assembly. In some cases the fix is to remove the facing or replace the batt with unfaced insulation rather than installing another faced batt.

Moisture problems should be solved before new insulation goes in. If the cavity also needs air sealing, vapor-control changes, or code review for the climate zone, an insulation contractor or building-performance professional should evaluate the full assembly rather than only the paper facing.