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  1. #1
    Join Date
    Jan 2010
    Posts
    1

    Default little spaces, higher r value?

    hi, we have a 1940 bungalow with 2x4 roof rafters. We have old insulation (r13) that I would like to replace with a stronger r value since we live in Michigan and heating costs are going up. The attic has a floor and is used for storage that we really don't want to loose as the house is only 820 square feet or we would just blow in insulation. Do you know if there is anyway to get a higher r value in that small of space (3.75 inches)?

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

    Default Re: little spaces, higher r value?

    Closed cell spray foam would be the best choice with about R21 or so.

    How much insulation is in place under the attic floor in the joist bays ?
    "" an ounce of perception -- a pound of obscure "
    - Rush

  3. #3
    Join Date
    Jan 2010
    Location
    Wisconsin
    Posts
    80

    Default Re: little spaces, higher r value?

    Hello, If I understand correctly, you have a open attic with a floor and wish to leave it that way? If so, pack down ceiling/roof rafters, or build a false ceiling and then insulate that ceiling and the walls around. Add rafter shoot vents the insulate roof rafters. Do not allow insulation to contact roof sheathing. This need air flow above. This way you don't lose your open attic room and you will then be insulated above that as well.Hope this makes sense.GregC
    Hidden Content GregC, President/Founder of Hidden Content

  4. #4
    Join Date
    Feb 2010
    Location
    Eastern MA
    Posts
    75

    Default Re: little spaces, higher r value?

    Closed cell foam is the way to go. The second method is basically useless. From my experience in fixing poorly performing houses as a spray contractor. If you are using the space for storage the foam should be covered for safety concerns in case of fire. There are intumescent paints that can be used, but they are expensive.

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