Will adding fiberglass insulation between the floor joists in my crawl space improve heat retention above?

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  • 1 month ago

    yes,,oh yes,while you are at it,lay half in plywood,,mark a spot and  do a circle cut to acommodate untility water,and electrical conduit,,another one for waste ,,if there is stand up room

    vents at both attic ends allows the house frame  and roof to breathe, and dispel moisture

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  • 1 month ago

    Absolutely YES. I did it last year and am kicking myself in the butt for not doing it sooner. My whole house is so much warmer. Last year I used about 200 gallons less in fuel heating oil.

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  • 1 month ago

    if you want to do it really well ..fit 100mm celotex 

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    • ron h
      Lv 7
      1 month agoReport

      Building codes MAY require that celotex be covered with some kind of sheathing b/c if it burns, the fumes will kill you.  Your city / county building dept can tell you.

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  • GTB
    Lv 7
    1 month ago

    it will help substantially

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  • 1 month ago

    well, yes.  some.  but adding the same amount in the attic will probably have a bigger effect -- heated air rises, you know

    • Splat1 month agoReport

      I had an extra layer of rock wool added to the ceiling a number of years ago.

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  • 1 month ago

    Yes .

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  • Edwena
    Lv 7
    1 month ago

    Yes, but it will not be as much as an exterior wall. Any open space in a ceiling between floors has ingress of outside air has to be heat or cooled. So plugging the void up with insulation reduces that volume. Same is true for your interior walls. They leak air through the outlets. So insulation will plug up those holes. An ultimate insulation job is every space in the wood frame. And while you are doing it, make your outside walls using 2x6 so you can use insulation with more r value. The additional cost of for wood is only a couple hundred of dollars. Believe it or not, there are not that many studs in the exterior walls of a house.

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