Batt insulation: Is the facing allowed to be left exposed?

[Jerry Peck - Codeman]

(From an e-mail question.)

Codeman,

My attic has fiberglass batt insulation installed and I can see the paper facing (the paper is facing up), is this correct?

I always thought the paper facing should not be visible. Am I wrong or is my builder wrong for installing the insulation that way?

Stan A.

[Jerry Peck - Codeman]

Stan A.,

What you are seeing is an all-too-common mistake builders make, usually it is the insulation contractor who makes the mistake, but they are a subcontractor of the builder, so it becomes the builder who is responsible, making it "the builder's mistake".

There are two reasons for the paper facing NOT to be visible after the insulation is installed:

1) The paper facing is a vapor retarder, the vapor retarder is required by code to be installed toward the warm-in-winter side.

The code I will reference is the International Residential Code (IRC) as most AHJ (Authorities Having Jurisdiction) have adopted the IRC for residential construction (construction of one-and two-family dwellings and townhouses) 3 or fewer stories high.

The 2006 IRC, in section N1102.5 states (underlining is mine):
- N1102.5 Moisture control. The building design shall not create conditions of accelerated deterioration from moisture condensation. Above-grade frame walls, floors and ceilings not ventilated to allow moisture to escape shall be provided with an approved vapor retarder. The vapor retarder shall be installed on the warm-in-winter side of the thermal insulation.
- - Exceptions:
- - - 1. In construction where moisture or its freezing will not damage the materials.
- - - 2. Frame walls, floors and ceilings in jurisdictions in Zones 1, 2, 3, 4A, and 4B. (Crawl space floor vapor retarders are not exempted.)
- - - 3. Where other approved means to avoid condensation are provided.

2) The insulation itself has a warning printed on each batt, on each paper facing, which states to the effect of (wording may vary depending on manufacturer of the insulation): "WARNING: RISK OF FIRE! This facing may burn! Keep facing away from heat sources! Facing must be in substantial contact with gypsum board or other approved building materials."

When the paper (or foil) facing is installed facing the warm-in-winter side of the insulation, the facing will, in an attic, be against the gypsum board ceiling as required.

Likewise, the paper (or foil) facing installed facing the warm-in-winter side of the insulation, the facing will, in a crawlspace, be against the subfloor, mostly like that will be wood.

Thus, when installed for the first reason 1), the installation will meet the second reason 2), and you will not see the paper facing after the insulation is installed.

Also, this does NOT mean the builder can just lay the insulation between trusses or ceiling joists (in the attic example), laying the insulation over wiring, over lateral wood braces, over etc., the insulation needs to be split in thickness to allow for the facing to be in contact with the ceiling, with the split fiberglass going under the lateral braces and up and over the lateral braces, with the wiring going down through the insulation or with the wiring below the insulation in such a way that the wiring (or plumbing, ductwork, etc.) does not interfere with the insulation laying properly in place against the ceiling.

Codeman