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  1. #1
    Join Date
    Aug 2007
    Posts
    2

    Default strange attic insulation type

    I am looking to add insulation my attic. It is a 1928 dutch colonial.
    I have a strange type (to me) of insulation there right now between the joists. It looks kind of like steel wool (not sure of the original color, grey now with dust). It will hold shape a bit when folded back but does not expand back to place like fiberglass does.
    Does anyone know what this is? What R value it might have?
    I want to put an R30 perpindicular over the old insulation and joists. I have also thought about an R38 but would have to take off the vapor barrier... does it lose the extra R value?
    Is that enought for a region that should have an R49 overall?

    Thanks!
    Last edited by jdezwaan; 07-15-2008 at 11:21 AM.

  2. #2
    Join Date
    Aug 2007
    Location
    The Great White North
    Posts
    4,045

    Default Re: strange attic insulation type

    Perhaps you could include a picture.
    Not sure ...could be old ditry compressed fiberglass , could be rock wool ( mineral wool ).


    I have also thought about an R38 but would have to take off the vapor barrier... does it lose the extra R value?
    I'm not sure what you are referring to regarding removing the vapor barrier.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  3. #3
    Join Date
    Aug 2008
    Posts
    54

    Default Re: strange attic insulation type

    Sounds like rock wool. Rock wool has a very good R-value, but is about the most miserable stuff in the world to come in contact with. Press your hand into it. If it feels like a pin cushion, it's rock wool. Where I live (northern Ohio) we bring attics up to R-38 by state standards, but climates like Minnesota or Wisconsin require more.

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