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Is polyiso roof decking acceptable as exterior wall insulation?

whitenack | Posted in Green Products and Materials on

A local roofing supplier is selling polyiso insulation boards for very cheap. Almost too cheap, and it has me wondering if it isn’t the same kind of rigid insulation I am looking for for exterior wall insulation.

The folks at the supply house wasn’t sure of the brand, so I don’t know any of the details, but they told me the R value of an 1-1/2″ sheet is R8.6. I have found “ValuTherm” which has the same specs. It says it is closed cell polyiso designed for roof decking and has a fiberglass facers.

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  1. whitenack | | #1

    Ah, looks like this question has been asked before, I just wasn't googling the correct terminology.

    Move along. Nothing to see here.

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