# Is this the way to insulate a rim joist?



## teeb57 (Oct 16, 2012)

I recently had my crawlspace encapsulated and noticed there was still cold air getting in to the living space directly above our crawlspace. I went down to see if I could find the source of cold air and found this. I'm sorry for the small fonts in these pics put the yellow arrow is pointing to exposed rim joists. They did what I thought was a superb job until I found cold air (not much) leaking in through these areas. I don't think the fiberglass insulation was the way to go with this. I welcome any and all expert opinions on this please. I'm wanting to call these folks back but need to know if this is the correct acceptable method of encapsulating.


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## joecaption (Nov 30, 2011)

Sure not the way I would have done it.
I would have used 2" foam and sealed any gaps with spray foam.


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## Windows on Wash (Aug 30, 2011)

Based on the lack of access and difficulty navigating that area, a froth pak (Spray Foam) is going to be your best application here.


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## hammerlane (Oct 6, 2011)

Hard to see from your pictures but does not look good. Here are some before and after pictures from my job. The before are with all batt insulation and the after is with the spray foam. Majority of my rim joists were about 6" deep and 9" in height


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## teeb57 (Oct 16, 2012)

From the looks of your pics, that looks like a very good job. I read some where that we need to be careful about using spay foam on rim joists however. I can't remember exactly but it seems I read that if the joist are below grade level spray foam shouldn't be used. 

Thanks for the photos


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## hammerlane (Oct 6, 2011)

teeb57 said:


> I can't remember exactly but it seems I read that if the joist are below grade level spray foam shouldn't be used.


Dont know why that would be the case. In any event mine are well above grade


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## joecaption (Nov 30, 2011)

*!*



teeb57 said:


> From the looks of your pics, that looks like a very good job. I read some where that we need to be careful about using spay foam on rim joists however. I can't remember exactly but it seems I read that if the joist are below grade level spray foam shouldn't be used.
> 
> Thanks for the photos


Just not true!


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## teeb57 (Oct 16, 2012)

joecaption said:


> Just not true!


 
I've looked for the article but now I can't find it. I think maybe I'm confusing it with the polyurethane foam.


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## Gary in WA (Mar 11, 2009)

Pages 6, 11; http://www.google.com/url?sa=t&rct=...zvd4mRKnTW5KfaQ&bvm=bv.55617003,d.cGE&cad=rja

http://www.buildingscience.com/docu...joist/files/bscinfo_408_critical_seal_rev.pdf

Gary


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## teeb57 (Oct 16, 2012)

Gary in WA said:


> Pages 6, 11; http://www.google.com/url?sa=t&rct=...zvd4mRKnTW5KfaQ&bvm=bv.55617003,d.cGE&cad=rja
> 
> http://www.buildingscience.com/docu...joist/files/bscinfo_408_critical_seal_rev.pdf
> 
> Gary


Thanks for that Gary,

I see that foam is ok I guess so long as it's not open cell.


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