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Weird (but free!) rigid insulation - any good?

Post in 'DIY and General non-hearth advice' started by FGZ, Jan 31, 2012.

  1. FGZ

    FGZ Member

    Joined:
    Nov 19, 2010
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    Loc:
    N.Shore MA
    Check it, free from a local manufacturer. They're insulating some of their machines, these are the scraps, original use has something to do with roofing. Looks like a basic ~3" thick rigid foam insulation, but both faces are a sturdy cardboard, not the typical foil vapor retardant.

    [​IMG]

    I'm wondering if I can use it in a crawlspace under a bathroom. If so, any special installation needed? If humidity will be a problem for it there, I hope I can just stack it in the attic. I know there is some moisture movement through there as well, but nothing like a crawlspace. Think it's any good for either of these applications?


    Thanks for any advice or suggestions, I'd really like to use this to make a difference in how well the house holds heat.

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  2. mbcijim

    mbcijim Member

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    Loc:
    Schuylkill County, Pa
    We use it under rubber roofing every day. Pretty sure it is r-21. 1"= r-7. I don't install it so that's all I know.
  3. JustWood

    JustWood Minister of Fire

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    Roofing application,,, correct.
    Thats good stuff.
    Years ago I hauled hundreds of tons of that to the landfill off school roofs. It walks outta the dumpster nowadays before it leaves the job.
  4. peakbagger

    peakbagger Minister of Fire

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    Give Tom in Maine a PM, he uses similiar materials for his tanks and I think he used to sell surplus foam
  5. Ehouse

    Ehouse Minister of Fire

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    Be careful not to create a vapor barrier holding moisture in. If it were me, I'd furr it out or run it x the joists and vent the air space, and not put it tight to the sub floor.

    Ehouse
  6. semipro

    semipro Minister of Fire

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    If I'm not mistaken that's polyiso foam with some sort of fiber facing, maybe fiberglass.
    We have collected some from dumpsters for home use and though the facing looks like gray cardboard I don't think it is.

    Edit: Maybe like this stuff: http://www.atlasroofing.com/tabbed.php?section_url=19
  7. FGZ

    FGZ Member

    Joined:
    Nov 19, 2010
    Messages:
    78
    Loc:
    N.Shore MA
    Thanks for the feedback!


    You may be on to something there, fiberglass backing would explain why I was pretty itchy after loading that truck bare handed. I'm going to look it over more closely and see if it's similar to the link you posted, esp because they spell out installation and other instructions.

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