# Insulation question



## Leonard (Dec 19, 2009)

I am pondering insulating at least the top 4' of my foundation walls inside.  The area is unfinished and will remain that way as we have more than enough living space, there is no source of heat even the boiler doesn't give off anything and I already have R-19 on the ceilings.  Does it make sense to insulate the walls at all?


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## velvetfoot (Dec 19, 2009)

I'd say no, but you could've had more than R-19 in the ceiling I'd imagine.


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## Leonard (Dec 19, 2009)

I guess I could double it up


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## velvetfoot (Dec 19, 2009)

I have it my ceiling.  I hate when I have to mess around it.  I always wind up coughing even if I breathe just a little, forgetting to wear a mask.
I put foam on the walls.  Not sure why.  It does stay warmer down there though.  It used to get pretty darn cold down (as I recall a few degrees above freezing) there with the wood insert on and upstairs heat not on.  It also helps with condensation and stinkiness in summer.  Downside of that is it's expensive.  You still have to cover that with sheetrock for fire resistance.  I was thinking of taking down the ceiling fiberglass now, but probably will cover it with sheetrock.  I imagine that it would provide some sound block.  The building science guys don't seem to like the fiberglass in a bag that go on the foundation walls-moisture and mold inside.  I'd block up any holes you might have down there esp. in the rim joist area.  Insulation in that area might help as well.


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## benjamin (Dec 19, 2009)

There are advantages to insulating the outside of your foundation, but generally it's a PITA.

The best way to do your inside is spray foam.  Pull out that fiberglass that's jammed into the rim joist area as if it's supposed to do something.  Blow the dust out with a leaf blower or air hose.  Spray it.  It doesn't take much thickness to be effective.  Most of the benefit is from sealing everything up.  Some use the two tank disposable setup for this kind of work, or you could get a pro to do it.  I was told $1.60  a square foot for the minimum thickness, which seemed like a bargain to me, considering the quality of the finished product.  

If you do go with the do it yourself kit, be sure to follow the directions, lots of people end up with less than advertised results.

I've been happy with using sheet foam, pink or aluminum faced, cut to fit and foamed in place with great stuff.  It's cheaper but more time and not as good a seal.


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## stephenmoore (Dec 19, 2009)

I agree with Benjamin, the spray foam is the best option for cold and moisture, it's a tricky area with your rim joist and exposed concrete. The closed cell sprayfoam is the clear winner.


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## velvetfoot (Dec 19, 2009)

I put the foam on the inside of the wall.

I also did the board foam cut and caulk in the rim joist thing, to multiple thicknesses.
I agree, spray foam in that area would've been way easier.

Here's a thread.  Ugggh.  I get tired thinking about it.

https://www.hearth.com/econtent/index.php/forums/viewthread/31340/

Now, this is multiple layers right out to the end.  Ugggh.  I did a rough estimate of how much it cost too once.  Ugggh.


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## coolidge (Dec 19, 2009)

We have  been in hundreds of basement in the past two years doing just the rim joist and down the foundation wall three feet. We install two inches of foam(R-14) and then cover with the thermal barrier, for about 3.00 sq ft. It is a longer payback, but if the oil boiler is running alot it will keep it nice and cozy.


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## stephenmoore (Dec 19, 2009)

I feel your pain about insulating the rim booard. Working as a carpenter I have had to do it enough to know I would never do it for free, not even for myself. I watched the spray foamers do my whole basement rim in a little over an hour. It was well worth it, and vapour barrier at the same time. We always use acoustic caulk by tremco, the horrible black stuff that sticks to everything, but never dries up. Oh well now that its done you'll never have to go there again.


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## DBoon (Dec 19, 2009)

I had my above ground basement walls (about 3') done with 2" of closed-cell spray foam, and I made sure the spray foam sealed over the tops of the hollow-core concrete block walls that the above ground walls rested on.  My basement used to be ~48-50 degrees in the depths of winter with the boiler running.  Now it is is about 52-54 degrees without the boiler running (woodstove running instead).  So it helps.  This cost me ~$2000.  I don't think the payback is as great as insulating the basement ceiling (which I did also), but it is effective.


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## stephenmoore (Dec 21, 2009)

Love the Minutemen avatar, we miss the other D. Boon. Double nickels on the dime...


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## DBoon (Dec 21, 2009)

Yes, I remembered a D. Boon posting after I created my avatar.  Couldn't resist using the "What makes a man start fires" album cover image.  I thought it was pretty clever and someone got it on my 2nd post.  

Double Nickels on the Dime likely (and we'll start some controversy here) the best rock album of all time.


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## stephenmoore (Dec 21, 2009)

No arguements from me on that one.


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