Question - Which way should paper face on insulation?

Answered by: Marilyn Sanders  |  Category: General  |  Last Updated: 22-06-2022  |  Views: 1150  |  Total Questions: 12

Regardless of whether fiberglass insulation is installed in a wall, attic, or crawlspace; the paper facing should always face toward the inside of the home. That's because the paper contains a layer of asphalt adhesive which prevents water vapor from passing through it. In order to prevent condensation from forming, a vapor barrier should be placed on the warm side of your insulation to stop warm, moist air from condensing on a cold surface inside your wall. In cold climates like Canada, for most of the year the vapor barrier should be on the inside of the insulation. In an upside down installation, where the paper faces the unheated portion of the home, moisture from the humid inside air can condense and become trapped inside of the insulation during cold winter months. This will likely result in fungal growth (mold) and rot. There are two basic types of vapor barriers used with exterior wall insulation. The most common is paper-faced insulation. The insulation is installed into the wall cavity with the paper facing into the house. This is very important — the paper, which is the vapor barrier, always faces the warm side of the house. Faced insulation has Kraft paper on one side to act as a vapor retarder and help prevent moisture from entering the wall cavity. Unfaced insulation is insulation only, for use when a vapor retarder isn't needed.

https://homeguides.sfgate.com/install-poly-over-insulation-51602.html

The special paper lining one side of the insulation is sufficient to block moisture and air. Some builders choose to attach a separate vapor barrier even with faced insulation, however. It doesn't hurt anything. The result, when finished, is a super-insulated wall with a foam vapor barrier instead of sheet plastic.

https://homeguides.sfgate.com/use-plastic-vapor-barrier-walls-27385.html

The standard installation of a plastic vapor barrier is between the studs and the drywall, but there are some exceptions to this. In exterior walls that are below-grade, like basement walls, plastic should not be used at all.

http://www.ashireporter.org/HomeInspection/Articles/The-Word-Vapor-Barrier/1722

Air barriers improve a home's energy efficiency and they reduce the flow of moisture-laden air into areas where the water vapor can condense. Asphalt felt, Grade D paper and house wraps such as Tyvek® are moisture barriers and are air barriers if correctly installed, but they are not vapor retarders.

https://www.kompareit.com/homeandgarden/insulation-compare-faced-vs-unfaced.html

Faced insulation is a type of blanket insulation that is typically made of fiberglass. It differs from unfaced insulation only in that it has a vapor barrier (also called vapor retarder) that blocks moisture from moving from one space to another. The vapor barrier is usually made of kraft paper.

https://blog.celotex.co.uk/technical/vapour-control-layer-vcl-celotex/

Vapour control layers are positioned to the inside of the insulation in order to minimise the amount of warm moist air entering the construction. Breather membranes are positioned to the outside of the insulation acting as a weather barrier while still allowing moisture particles to escape from the inside.

https://home.howstuffworks.com/home-improvement/repair/best-way-to-apply-vapor-barrier-in-an-inside-

Installing a vapor barrier on the (warm) interior wall of your cement brick house will prevent condensation and reduce air leakage through your walls and insulation. Because no vapor barrier can be perfect, and some water may still get in, you must create a venting path for the water to get through the insulation.

https://www.certainteed.com/insulation/fiberglass-insulation-and-vapor-barriers/

Vapor barriers applied over the face of the insulation provide additional benefits in the fight against moisture. Usually composed of a thin film, such as polyethylene, vapor barriers are used to retard or prevent water vapor diffusion into a wall, ceiling or floor during the cold winter.

https://www.americover.com/blog/which-mil-thickness-crawlspace-vapor-barrier/

Right Mil Thickness For Your Crawlspace Vapor Barrier. Vapor barrier thicknesses range from 6 mil to 20 mil, with 6 mil being the bare minimum and 20 mil being the most heavy duty and puncture-resistant.

http://www.renovation-headquarters.com/insulation-wall.html

When using kraft faced insulation, an interior finish material, such as drywall, should be installed as soon as the insulation is in place. Unfaced batts may be left exposed unless local building codes require otherwise.

https://www.houserepairtalk.com/threads/can-i-double-vapor-barrier.5641/

You should never double a vapor barrier. When a wall does get wet, you could end up with moisture between the vapor barriers and it will mold before it dries. This has been an issue for homes with insulated foam board on the exterior and a vapor barrier inside.

https://www.jlconline.com/how-to/insulation/q-a-ceiling-vapor-barrier-yes-or-no_o

All attics — vented or unvented — should have an air barrier (a properly detailed airtight drywall ceiling, for example) regardless of climate. Omitting a ceiling vapor barrier by arguing that "you have to let the moisture escape" or "because the house has to breathe out the top" is actually correct, in a way.

https://www.iko.com/comm/introduction-to-vapour-barriers-and-vapour-retarders/

The purpose of vapour barriers A vapour barrier is an important component in building construction. Its purpose is to help prevent water vapour from reaching building walls, ceilings, attics, crawlspaces or roofs, where it can condense and cause building materials to rot or grow mould.