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  1. #1
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    Question spray foam insulation

    To make our home more energy efficient, the pink insulation from our home's attic 'floor' was removed and 8" of Sealection 500 (open-celled, semi-rigid polyurethane foam system) was sprayed directly to the back of the blue board ceiling that runs through the house's interior.

    Two questions:

    a) After adding the 8" of foam do we need the original pink insulation and will putting it back on top of the cured foam actually do anything significant to make the house more insulated?

    b) Since the foam was sprayed directly to the back of the blue board of the house's interior ceilings and the insulation is an open-cell product do I have to worry about the humidity from below (the air inside the house) or above (the outside air in my attic) wicking into the foam and eventually making it wet and potentially moldy?

    I have heard lots of conflicting information from various sources in the insulation industry and I am not sure who to believe.

  2. #2
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    Default Re: spray foam insulation

    I agree pretty much with jkirk .... the open cell will breath.
    Also the foam itself isn't food for mold.

    As for putting the fiberglass batts over top of the foam .... this shouldn't be an issue.
    It will add to the overall insulation value in your attic .... besides it's a recycle situation I agree with instead of just tossing it away . Also it didn't cost you anything and it doesn't cost a dime to use .... so why not reuse it.


    BTW .... around here R50 is becoming the norm.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  3. #3
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    Default Re: spray foam insulation

    Quote Originally Posted by keithp View Post
    To make our home more energy efficient, the pink insulation from our home's attic 'floor' was removed and 8" of Sealection 500 (open-celled, semi-rigid polyurethane foam system) was sprayed directly to the back of the blue board ceiling that runs through the house's interior.

    Two questions:

    a) After adding the 8" of foam do we need the original pink insulation and will putting it back on top of the cured foam actually do anything significant to make the house more insulated?

    b) Since the foam was sprayed directly to the back of the blue board of the house's interior ceilings and the insulation is an open-cell product do I have to worry about the humidity from below (the air inside the house) or above (the outside air in my attic) wicking into the foam and eventually making it wet and potentially moldy?

    I have heard lots of conflicting information from various sources in the insulation industry and I am not sure who to believe.
    If there is any type of cover, liner, facing layer on your fiberglass batts i'd remove that before recycling for re-installtion in the attic, because that moisture/vapor facing could cause a problem sandwiched in or on top of the insulation (trapping condensing water vapor and causing /developing the issues you've expressed concern about - wet insulation - rot/mold/mildew framing, etc.).

    If you "need" it, couldn't say. You didn't provide any details to know if it was needed, example: location, climate, roof/attic situation, venting, etc.

    When it comes to insulation questions climate, geographic location, construction details and such are important to know, as what is best in one situation can be bad or worse in another.

    The buildingscience.com website is a very good first read resource if you'd like to look up information specific to your region, construction type, etc.

  4. #4
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    Jan 2008
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    Smile Re: spray foam insulation

    keithp,

    Thank you very much for your kind private message, you are most welcome. Good luck with your project.

  5. #5
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    Default Re: spray foam insulation

    Keithp .... I too thank you for your private message..... glad to help out.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  6. #6
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    Default Re: spray foam insulation

    Standards for R values vary depending on location. In Ohio, the state standard is R-38, but in colder climates, like northern Canada and Alaska the standard could be as high as R-60.

  7. #7
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    Dec 2008
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    Wink Re: spray foam insulation

    Sealection is made by Demilec. Their ****** brochure repeatedly states that Sealection provides an 'airtight seal'. Moisture is carried by air, therefore, Sealection doesn't 'breathe' in either direction, and nowhere in their brochure do they make that claim. The 'open cell' characteristic refers to the cell walls, which are broken, and permit it to trap air, which in turn is where the insulation value comes from.

  8. #8
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    Default Re: spray foam insulation

    Quote Originally Posted by massbear View Post
    Sealection is made by Demilec. Their ****** brochure repeatedly states that Sealection provides an 'airtight seal'. Moisture is carried by air, therefore, Sealection doesn't 'breathe' in either direction, and nowhere in their brochure do they make that claim. The 'open cell' characteristic refers to the cell walls, which are broken, and permit it to trap air, which in turn is where the insulation value comes from.
    I'm not familiar with that particular brand of product and can't comment directly on it.

    However .... if it is an open cell polyurathane foam it does breath as is the nature of this product. It does provide an air barrier because of it's density though it does allow vapor to pass through. In certain applications and locations there is a need for an additional vapor barrier (retarder) to be in place because the open cell will pass vapor.

    This is one reason this type of foam is preferred in certain applications over the closed cell which does not breathe.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  9. #9
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    Aug 2009
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    Question Re: spray foam insulation & vapor barrior

    I intend to have open cell spray foam installed in an attic/living space. After the spray foam is sprayed against the roof decking, should I use a vapor barrier, such as tyvek, over the foam insulation before installing sheet rock?

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