# Insulation : Faced and unfaced



## Alan (Apr 12, 2006)

Argh. I think i found the answer I was looking for.


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## Alan (Apr 12, 2006)

Ok, but I do have a question that I can't seem to answer by looking at the requirements that I found.

Is insulation required between floors? If so, what R-Value does it need to be?


zone 4C.


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## Gary in WA (Mar 11, 2009)

Only between a conditioned (living space) and an unconditioned one--- crawlspace/main floor, attic/upstairs floor. 

http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_11_sec002.htm

Vapor barriers: http://www.buildingscience.com/docu...heet-310-vapor-control-layer-recommendations/

Certain exterior insulation mute the v.b. requirement: after reading, hit "next section" , etc., etc., etc.http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_6_sec001_par003.htm

Gary


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## Alan (Apr 12, 2006)

Hey Gary,

I was reading another thread on this topic and I saw that you said something about taping the seams on the facing. What kind of tape is normally used for that? Plain old duct tape?

To take that one step further, I assume it would be a good idea to tape around electrical boxes and pipes that stick through the facing as well?


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## Gary in WA (Mar 11, 2009)

Alan said:


> Hey Gary,
> 
> I was reading another thread on this topic and I saw that you said something about taping the seams on the facing. What kind of tape is normally used for that? Plain old duct tape?----
> 
> ...


-------- 

Air sealing is a different subject. Yes, air seal the drywall (ADA): http://www.buildingscience.com/documents/information-sheets/air-barriers-airtight-drywall-approach/

Make sure the insulation is touching the drywall to prevent convective loops, though low-density f.g. has inherent c.l.'s: http://www.buildingscience.com/documents/information-sheets/installation-of-cavity-insulation/ Don't inset staple walls.

Gary


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## Alan (Apr 12, 2006)

Very good reads there. Thanks a lot.

Something else crossed my mind while I was reading that, so here it is : 

If you're supposed to cut the insulation to fit tightly around obstructions (IE : electrical boxes) what should be done between the electrical box and the subsiding in an exterior wall? Compressing the insulation to fit isn't a good idea from what I was reading. What other option is there?


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## Nailbags (Feb 1, 2012)

Alan said:


> Very good reads there. Thanks a lot.
> 
> Something else crossed my mind while I was reading that, so here it is :
> 
> If you're supposed to cut the insulation to fit tightly around obstructions (IE : electrical boxes) what should be done between the electrical box and the subsiding in an exterior wall? Compressing the insulation to fit isn't a good idea from what I was reading. What other option is there?


when you install around a electrical box you slit the batt place half behind it then cut the front out top bottom then fold in and place to the side. I whis I had a photo of how to do this. Next time i do a insulation job I will take photos and post.


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## Alan (Apr 12, 2006)

Nailbags said:


> when you install around a electrical box you slit the batt place half behind it then cut the front out top bottom then fold in and place to the side. I whis I had a photo of how to do this. Next time i do a insulation job I will take photos and post.


That would be awesome. 

:thumbup:


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## Alan (Apr 12, 2006)

I was looking at some videos and they brought me to this : 


Since my exterior walls are 2x4 would it be better to spray foam behind the electrical boxes? Would I get better R-value out of 1 to 1-1/2" of spray foam than I would with fiberglass batts cut to fit?


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## Windows on Wash (Aug 30, 2011)

That is correct.

Seal up the electrical boxes as well so that when you drywall, the wall is tight on both sides.

When the wall is exposed, seal every gap, crack, or air loss point you can spot.

Air loss is far more critical to efficiency than R-Values in most cases. Air loss is also much more responsible for moisture issues than faced vs. un-faced insulation.

It carries about 100X as much water as a faced vs. un-faced question.


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