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Insulating attic

Post in 'DIY and General non-hearth advice' started by Mrs. Krabappel, Jun 26, 2011.

  1. Don2222

    Don2222 Minister of Fire

    Joined:
    Feb 1, 2010
    Messages:
    7,044
    Loc:
    Salem NH
    Hello Kathleen

    Don't forget about the Foil to keep your house really cool in the summer!!

    The Reflectix foil at Home Depot will keep your house 10 degrees cooler in the summer!!
    No kidding my attic was 115 degrees the other day in the late afternoon and my neighbors was 125 Degrees!!

    See pics below

    1. Add Pink proper vents in attic ceiling from soffit vents to ridge vents
    2. Staple foil over the pink vents
    3. Add 2x2s added to the 2x4s in the attic floor
    4. Roll down the foil
    5. Roll down faced Pink Fiberglass R19 6" thick to fit in newly created 2x6s
    6. Crisscross with unfaced fiberglass R30 9" thick

    Total R53

    Foil in Ceiling
    Reflects heat back in winter to keep house warmer

    Foil in Roof
    Reflects heat out in summer to keep house cooler

    Really works!!

    Attached Files:

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  2. nate379

    nate379 Guest

    Uh, those vents are supposed to just go at the bottom and just a bit over the top of the insulation. You don't run it from soffit to ridge!
  3. Don2222

    Don2222 Minister of Fire

    Joined:
    Feb 1, 2010
    Messages:
    7,044
    Loc:
    Salem NH
    Hello Nate

    By running the vents from soffit to ridge like they do in a cathedral ceiling, it keeps the cold soffit air separate from the warm attic air to keep the house much warmer in the winter. If the air was not separate, the cold soffit air will suck out the heat in your house like a hover vacuum cleaner!! Try it, it really works!!

    Also, I made insulated doors for the gable vents so I can close them up in the winter. Another way to loose large amounts of heat!! It is a difference you can feel downstairs and all the way to the bank!!!

    See pics below:

    Attached Files:

  4. Mrs. Krabappel

    Mrs. Krabappel Minister of Fire

    Joined:
    Jan 31, 2010
    Messages:
    1,568
    Loc:
    Blue Ridge Mountains NC
    Great info, thanks for the pics! While the bulk of the prep will be me, I can certainly get help when needed for bigger jobs. Also, while we do have a more temperate climate than further north, we spend many days below freezing and usually have 1-2 spells a year of single digit temps.

    I talked to my brother about this. His in-laws just built a "family compound" with three new large modular home. The guys putting in the insulation put the big rolls of fiberglass. No blown in cellulose or fiberglass.
  5. nate379

    nate379 Guest

    I have catherderal ceiling in my house, but there is still 4ft or so from ceiling to roof.

    I see what you are trying to do, maybe it works, but around here it's norm to vent attic well, insulate well and no ice dams/icicles or mold. Attic temp is about outside temp in winter. BUT that is reason for R50-R60 insulation on top of ceiling (attic floor)... and of course vapor barrier.

    Seems to work well in my house. I heated ~1400 sq ft of house last winter on about 3 cords of wood (birch, cottonwood and spruce). House was kept around 75*.


  6. Wallyworld

    Wallyworld Member

    Joined:
    Mar 24, 2009
    Messages:
    205
    Loc:
    Downeast
    Taking the Styrofoam vent channels all the way to the ridge vent doesn't seem right. How does the moisture get to the ridge vent? Seems like it would be the same as putting in a pipe line from soffit to ridge
  7. Don2222

    Don2222 Minister of Fire

    Joined:
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    7,044
    Loc:
    Salem NH
    Hello

    There is still a space at the peak so any moisture can escape. The bathroom fan is vented outside like it should be.

    The cool air from the soffit to ridge under the styrofoam works well to keep the roof cool and no ice dams.

    The air inside the attic in the winter now with the gable vent doors closed is warmer than the outside and keeps the house warmer!
    No cold breezes coming in to suck out the heat anymore!!! YAY

    Attached Files:

  8. nate379

    nate379 Guest

    How about the summer temps up there? I bet it's ROASTING! My attic will get close to 100* when the sun is beating down.
  9. gzecc

    gzecc Minister of Fire

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    Sep 24, 2008
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    3,795
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    NNJ
    I am a contractor and have seen many inappropriate recessed light applications. If you have recessed lights in your ceilings breaking the barrier into an unconditioned space, this is where most of your conditioned air is escaping. Remove the recessed lights. If they are not "IC" they were probably not installed by a licensed electrician and you probably have inadaquate electrical wiring to boot. This of course is a stretch without seeing it but, I've seen my share.
    Eliminate the recessed lights (when they break the barrier between conditioned and unconditioned space).
    Make sure you have plenty of soffit intake air flow and ridge air flow.
    Then insulate as much as you want.
    The last thing you want to cause is ice daming. I assume you get snow in the winter.
  10. Don2222

    Don2222 Minister of Fire

    Joined:
    Feb 1, 2010
    Messages:
    7,044
    Loc:
    Salem NH
    Hi Nate

    The foil reduced the summer temps by 10 Degrees !! So where I am, the attic on a sunny afternoon was 125 Degrees F with no foil. Now it is 115 Degrees F with the foil. That saves alot of air conditioning costs!! When I run the air conditioner all I need is the lowest setting!!

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