Basement Insulation

Discussion in 'The Garage' started by 13, Feb 14, 2013.

  1. 13

    13 __________

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    So I'm getting ready to drywall my basement and had a question. Is it bad to insulate the ceiling? I'm looking to put some sound proofing but don't want to mess up the way the house "breathes". My major concern is I don't want to trap any moisture.

    I'm planning to put in baseboards (hydronic) on their own zone if that has any impact.


    :ear
    #1
  2. lnewqban

    lnewqban Ninjetter

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    I don't know, but you could check with your state building code.

    Normally, a dehumidifier in the basement solves any humidity issues.
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  3. gsweave

    gsweave Yinz, blinkers are on, since 05

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    Unfaced batting, in the joists

    It will be fine:deal

    Walls? How good is your drainage?
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  4. the_gr8t_waldo

    the_gr8t_waldo Long timer

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    i also don't know about codes but, if you install "unbacked" fiberglass or rock wool insulation ( insulation without the vapor barrier)..the house will "breathe" the same as before the introduction of insulation. i belive the rock wool is the mat'l of choice for sound proofing/ heat insulation.
    #4
  5. 13

    13 __________

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    The walls were all insulated previously and there have been no signs of water in the basement. I re-graded the earth surrounding the house so the water runs away from the house.

    Yup. Thats the stuff I was going to use.

    Thanks for the tips guys.
    #5
  6. zap2504

    zap2504 Dave E.

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    There are better ways to soundproof between floors (like 2 sheets of drywall with a spacer), but a dense insulation will also provide some sound deadening. And you don't need to worry about a house "breathing". My experience as an energy auditor shows that most homes leak much more air into the outside than is good for the occupants. Unless you (air) tighten-up the air leaks to the point of reducing the "natural" air exchange to less than .35 air changes per hour you will still have plenty of fresh air (well, relatively fresh as it IS coming through all the cracks and crevices). The only way to really gauge a house's tightness/looseness is by measuring it with a blower door. Kraft-faced insulation between the floors will not affect air tightness.
    A couple things - kraft paper facing does not hinder moisture transfer like you might think (see: http://www.greenbuildingadvisor.com/blogs/dept/musings/do-i-need-vapor-retarder) and you should not be putting any kind of fiberglass or cellulose insulating material up against a basement block wall as it will absorb moisture that flows through the block (cement/cement block allows a considerable amount of moisture through it) and grow mold. See this for the proper way to insulate a basement wall: http://www.greenbuildingadvisor.com/blogs/dept/musings/how-insulate-basement-wall
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  7. TOTim

    TOTim Been here awhile

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    Don't drywall the basement ceiling. It's impossible to do any upgrades on the upper levels later. Insulation and T-Bar is fine.
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  8. 13

    13 __________

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    The main floor was insulated with 3" closed cell spray foam when we gutted it. There are zero drafts. I plan on doing the same upstairs when we dormer.

    As far as access goes we ran all the pipe and wire for the dormer when everything was open so there is no reason to access anything in the ceiling. 95% of the pipe/wire runs up on the utility side of the basement which will remain open. I've thought about the difficulty that may arise if there is a leak in a heating pipe or something but I can't stand the look of a drop ceiling so I'll take the chance
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  9. Wasser

    Wasser Spilt my beer

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    That's what I did in mine.

    Sure seemed to help with sound & temperatures on both levels.

    Something the OP should think about is picking up some poly line or string and running it the length of the joists before he puts the insulation in. Use a staple gun and attach it to the sub floor plywood underneath at two ends. That way, he has a string to pull a cable or wire through in the future real easy. :deal

    We don't have to worry about breathing for humidity here where I live. If we have humidity, its raining. And, that's only 3 times a year. :lol3
    #9
  10. zap2504

    zap2504 Dave E.

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    If that was 3" of closed-cell foam on all 6 surfaces, then you BETTER install an ERV or HRV to provide adequate fresh air! If the 3" was only on the sidewalls, then I'd bet you still have plenty of air flow through your house (most air flow is out to the attic and into the basement).

    If you are talking about creating a dormered living area out of an attic, then yes - foam the whole roof joist/sidewall/dormer framing areas with as much foam as will fit (i.e., encapsulate the whole area and connect it to the sidewalls of the 1st floor). It will prevent many other problems down the road and allow for behind-the-kneewall storage without hampering the overall insulative value. Cape Cod-style houses are the worst to retrofit.
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  11. 13

    13 __________

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    It's a cape. There are two finished rooms upstairs now with peaked cielings and knee walls. We plan on ripping the current 2nd floor. Cantilevering 2' off the back and squaring up the front with a short attic on top. We only foamed the exterior walls on the first floor.
    #11