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Insulation problem>>>

Post in 'DIY and General non-hearth advice' started by pt0872, Nov 22, 2008.

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  1. pt0872

    pt0872 Member

    Joined:
    Oct 8, 2006
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    Loc:
    Carver, Mass
    House was build in 1958....I've done alot of remodeling and replaced the insulation in the dinning room and a few bedrooms.

    Before we bought the house the previous owners build an addition, a living room and a bedroom. These two rooms are FREEZING.

    They didnt leave me room to get under the floor in the new addition....it's a block foundation and I'd have to break out a few blocks to even think about crawling in there on my back. I can barely see under there but it is insulated and has a vapor barrier on the dirt floor. I believe the insulation is R-19. It's also R-19 in the attic which isnt very accessable either. So R-19 must also be in the walls which I cant afford to rip down to check.

    SO.....I'm considering blown in insulation for the attic and the foam board for the floor if I can get a big enough hole in the block to pull the sheets in there.

    Am I correct in thinking this will help warm the rooms? And what R value should I be looking at creating?

    We live in Carver, Ma and it's getting very cold here.

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  2. smokinj

    smokinj Minister of Fire

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    Loc:
    Anderson, Indiana
    r-50 over head and r-19 in the walls is good and the band board underneith is where i would pay speical attion too!
  3. Highbeam

    Highbeam Minister of Fire

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    R-19 is fine in the floors. That's what I just had installed this month. If you have R-19 in the walls then don't do a thing, that's great. Now the ceilings, if R-19, should be upgraded to more than R-38. Yeah, yeah, it's great to go R-50 everywhere but it's not worth it when you do the math especially when the existing material is pretty darn good and access sucks. The ceiling, improve the ceiling.

    Perhaps this addition was built without removign the old exterior insulation. Meaning, the wall that used to be exterior before the addition is now interior and is blocking heat transfer to the addition. Once you warm up the addition, does it stay warm? If so we are talking about a heating problem and not an insulation problem.
  4. dave11

    dave11 Minister of Fire

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    It's a myth that the ceiling of any room should be any better insulated than the walls or floor. Heat moves across any surface proportional to the temp difference between inside and outside, and inversely to the R-value of that surface. Heat moves equally in all directions, up or down. Hot AIR is what rises, but that's a real difference.

    The main reason ceilings are (usually) better insulated than walls/floor is simply because it's easier to do it. There's usually excess space in the attic.

    That said, if the room is cold, you want to increase the R-value of whatever surface currently has the lowest total R-value. That probably is the floor, as the subfloor under those rooms likely has the least intrinsic R-value, less than that of the walls. Now, it might not be easy, or even possible, to do so. It depends on the construction of the rooms and the type/amount of insulation already in place. Keep in mind though that the higher you go with R-values, the less return on your money.

    Before spending a dime on more insulation though, I'd make sure you had completely sealed the crawl space under those rooms, so that cold air cannot circulate into it. That way, heat passing through the floor will build up somewhat in the crawl space, and so will lessen the drive of heat leaving the room that way. I'd caulk every crack and try to make it airtight. You could install a seal-able vent if moisture is a problem there though in the Summer.

    I'd also make sure those rooms were air-sealed from above in the attic, if you can get to it.

    Lastly, as was already mentioned, are you sure the heat supply to those rooms is adequate? The best insulated rooms will still get cold if the heat supply is too low.
  5. billb3

    billb3 Minister of Fire

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    1. I'd want to know there was insulation in the walls.
    Too easy to have installed the existing insulation in the floors and ceiling in 1980.
    If the wall is sheetrock it's not that hard to penetrate an inspection hole and patch.
    Know anyone with a thermal camera ?

    2. Check for air infiltration. Sealing the wind out has many times the worth of
    Leaks / wind will go right through fiberglass insulation.
    Finding every leak will save much more $$$ per squirt of foam sealer (or whatever the remedy is) than an extra inch or two of insulation will.
    For every cubic inch of cold air coming in on a windy day, a corresponding cubic inch of heated air is going out.

    3. wet insulation has little to no value.
    If the original color insulation is black from dirt you have an air leak. Find it and seal it.
    If it is moldy replace the insulation, find the leak or moisture cause and cure it.

    properly installed insulation is worth considerably more than when it is not.


    heat rises
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