# Bubble-Foil Insulation on Basement Walls?



## huesmann (Aug 18, 2011)

Is it kosher to use bubble-foil insulation on basement exterior walls? TIA.


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## AGWhitehouse (Jul 1, 2011)

foil facings are usually considered class I vapor retarders and are not recommended in basement spaces at it traps moisture and enhances the chances for mold growth.


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## huesmann (Aug 18, 2011)

How come the "typical" installation includes a vapor barrier sheeting under thhe drywall?


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## AGWhitehouse (Jul 1, 2011)

huesmann said:


> How come the "typical" installation includes a vapor barrier sheeting under thhe drywall?


If you're looking at a book/website that calls for a vapor barrier on the interior side of the basement wall insulation assembly then throw it out.

http://www.buildingscience.com/docu...=resources/high-r-value-foundation-assemblies

It's not recommended because of trapped moisture within the cavity space. Moisture comes for the exterior of a foundation and migrates towards the interior.

That "typical" installation is for above grade walls where moisture within the wall has the opportunity to dry to the exterior. Basements can't dry to the exterior.


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## huesmann (Aug 18, 2011)

What is recommended for existing construction masonry walls to be finished with drywall, in the Mid-Atlantic?


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## AGWhitehouse (Jul 1, 2011)

I'm assuming you are talking about a masonry foundation wall.

I would recommend following this section as closely as possible: http://www.buildingscience.com/docu...=resources/high-r-value-foundation-assemblies

You can look other options and the results of the tested assemblied by clicking on the "High R-Value Foundation" on the left side of the page.


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## huesmann (Aug 18, 2011)

Thanks, I appreciate it.


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## carlosc (Nov 23, 2011)

There are some helpful answers to foil insulation located here:
http://www.farmtek.com/farm/supplies/ExternalPageView?pageKey=EXTERNAL_PAGE_3005


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