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Siding house in Maine

dbernard | Posted in Energy Efficiency and Durability on

I am stripping and resideing my house I was looking at a product called prodex insulation it says it works as a vapor barrier as well as a high r-value what do you think of this type of product thanks

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  1. STEPHEN SHEEHY | | #1

    I looked at the Prodex web site. R-16, and only 3/16" thick. Must either be a miracle or bogus. I'm leaning toward the latter.

  2. GBA Editor
  3. Expert Member
    Dana Dorsett | | #3

    Neither a miracle nor bogus- but you have to read the fine print.

    It behaves at R16 if it's horizontal with the warm side up with a couple inches of air between it an the top & bottom sheathing of the assembly. That would be a summertime performance of a flat roof with 2x6 rafters, with the Prodex installed mid-way in the cavity, and a fully enclosed by a ceiling layer below.

    Wintertime performance in a horizontal application would be much lower than R16 due to the convective transfer within the cavities when the cold side is up.

    Performance in vertical installations is lower still.

    It's fairly useless in most locations, and almost COMPLETELY useless as wall insulation in a wall in Maine even if you build out some air gaps on both side.

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