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Community and Q&A

Double Bubble for Underslab insulation

k8RQsvj3yc | Posted in General Questions on

I found a thread on GBA “discussing” the pros and cons of using foil based radiant barrier products for insulation of ducts and attic spaces. One of the foundation contractors bidding on my new house project wants to use “Double Bubble” under my basement and garage floors. Can I believe the hype in this application? Would appreciate any thoughts or advice.

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  1. wjrobinson | | #1

    Jim, searching this site you will find that xps or eps foam is what to use underslab.

    Well drained gravel, then your foam, then your poly vapor barrier, then pour concrete. Don't worry about poly getting holes since it is tight to concrete.

    My concrete contractor places the foam for me at no extra charge as he likes to start at checking out the gravel placement first before he begins his work.

  2. gusfhb | | #2

    The contractor is ummm, intellectually challenged. Any product subject to FTC action is to be avoided

    I would find a new contractor

  3. GBA Editor
    Martin Holladay | | #3

    Foil-faced bubble wrap has an R-value of R-1 or R-2, and it usually costs more than R-5 rigid foam.

    People who sell foil-faced bubble wrap for use under slabs are scam artists.

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