Faced Or Unfaced Insulation In Attic Knee Walls

The problem with many kneewalls is that they have fiberglass batt insulation with nothing covering them on the attic side as shown in the photo below.

Faced or unfaced insulation in attic knee walls.

Kraft faced insulation includes a paper vapor retarder which helps prevent mold and mildew. Unfaced insulation the type without paper is what you would use if you are adding insulation to your attic or to place between floors when living space is above and below. The kraft paper itself is highly flammable. The kraft paper on one side of faced insulation keeps moisture from spreading throughout the walls or ceiling.

Unfaced batt insulation is often used for beefing up the r rating with the r rating being the insulation rating scale that says how much or how effective insulation needs to be in that space. Faced or the type with paper is typically used in first time applications such as in walls ceilings floors and in crawl spaces. The advice seems to be all over the map. I have a standard knee wall that i would like to insulate.

The same applies to faced unfaced and other kinds of insulation products. It is a non ventilated space so i am concerned about mold. So in an attic the paper faces downward and in a crawl space it faces upward. That would seem to cover everything but i have also read that you shouldn t insulate the rafters should i use faced or unfaced batts does it really.

Should i use a triangular approach putting batts on the attic floor wall and rafters. If the attic doesn t have any existing insulation use faced insulation with the paper facing toward the heated living space. What happens then is that the batts don t make contact with the air barrier the drywall air moves through and around them and they fall out of the attic kneewall. Probably in more place than you think.

In addition to walls and attics insulation should be installed in ceilings with unheated spaces basement walls floors above vented crawl spaces cathedral ceilings floors over unheated garages or porches knee walls and in between interior walls especially bathrooms as well as ceilings and floors. Kraft faced insulation should be installed in exterior walls exterior basement walls and attic ceilings by pressing the product into the wall cavity with the paper side. You should only use faced insulation as the first layer of insulation. When local building codes require a vapor retardant faced insulation is one of the best options.

Unfaced means the insulation lacks a vapor retarder paper or plastic facing. Whether you choose faced or unfaced insulation for the attic depends on the. Any time you use a faced insulation the paper needs to be facing toward the living space. For many contractors the decision to use one kind of insulation over the other depends solely on preference rather than a by the book decision making process.

Insulation being unfaced doesn t mean it s a bad choice. It means ensuring that it s the right product for your space.