What is a Vapor Retarder
Saturday, June 12th, 2010 | Uncategorized
What is a Vapor Retarder?
Moisture in the air in the form of vapor is transferred along with heat. This is especially common in humid environments and in certain areas inside a home - such as bathrooms, kitchens and laundry rooms. When moisture vapor becomes trapped, mold and mildew growth can result. Vapor retarders keep the moisture in the air in your house from condensing in the insulated cavities.
Whether or not you need a vapor retarder depends on local building codes and your climate. Generally, in hot, humid areas using a vapor retarder is not recommended. In mixed climate areas, the vapor retarder is optional depending on the total design of a building. In cold climates, a vapor retarder is almost always needed.
The facing on faced insulation acts as a vapor retarder. If you need a vapor retarder and your insulation is unfaced, you must cover it with a polyethylene film.
Faced Insulation
This is insulation with a facing already attached to it. Facing acts as a vapor retarder and is commonly made from Kraft paper or foil, depending on the intended application. In addition to its thermal and acoustical properties, faced insulation is ideal for moisture control on exterior walls. The type of insulation you need depends on where the insulation will be installed, what R-values are needed, and your budget.
Unfaced Insulation
Unfaced insulation has no facing attached to it. This type of insulation is effective when controlling unwanted noise in internal walls and to assist with moisture control. Where vapor control is required, a separate vapor retarder can be used.
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