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For Moisture Control

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 laundries. When moisture vapor becomes trapped, mold and mildew growth can result. These can damage the home and present a potential health concern to the home's residents. Vapor retarders keep the water vapor in your house from condensing in the insulated cavities.

Whether or not you need a vapor retarder depends on your heating source and your climate. A vapor retarder may be required based on your local building codes, so be sure to check. 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.

JM's Kraft-faced and MR® Faced insulation provides a vapor retarder (The MR facing is treated to protect the product from the growth of mold and mildew).

Whether your vapor retarder is a facing or a film, it is usually placed on the warm-in-winter side of the wall. If you live in a cold climate, place the vapor retarder between the interior of your home and the insulation. If you live in a warmer climate, place the vapor retarder toward the outside of the wall cavity.

Product Listing

JM Spider® Custom Insulation System


JM Spider® custom insulation sprays-in filling all gaps and voids in your walls, significantly improving energy efficiency, sound control and family comfort.

ComfortTherm® Batts and Rolls


ComfortTherm® insulation is a lightweight, thermal and acoustical insulation made of long, resilient glass fibers bonded with an acrylic thermosetting Formaldehyde-free™ binder.

EasyFit® Batt Insulation


JM's EasyFit® Formaldehyde-free™ insulation is available unfaced or with kraft facing, and has vertical perforations for fitting non-standard wall cavities.

Kraft-Faced Batts and Rolls


JM's Kraft-Faced Batts & Rolls are made of naturally white, Formaldehyde-free™ fiber glass, reducing environmental concerns including the risks of poor indoor air quality and the effects of manufacturing on the environment.

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