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best way to improve insulation inside walls


PaulSC's Avatar
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06-02-15, 03:29 PM   #1  
best way to improve insulation inside walls

I am in NJ and my place has very little insulation behind the drywall....Looks like very old R9 or R13 at the most that settled in some spots.

This old insulation has kraft facing the drywall so I know shouldn't add any insulation on top of it.

which would you do:

1. remove and discard of all the old insulation - Install all new kraft faced insulation
2. Remove the old insulation, place the new unkrafted insulation and then put back the old insulation.

any other options ?
Also...what's recommended in NJ ?Would R19 be enough ?

Thanks!

 
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XSleeper's Avatar
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06-02-15, 03:54 PM   #2  
R-13 fiberglass is made for a 2x4 wall. R-19 fiberglass is made for a 2x6 wall. You should not stuff R-19 into a 2x4 wall because then it wouldn't be R-19 anymore if you compress it.

It would probably help if we knew your grand plan, because removing all the drywall just to replace your existing insulation with R-13 insulation would probably not be a good investment. Tell us how thick your walls are, and whether you are planning on new trim or not. Are you doing this in one room, one wall, or the entire house?

 
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06-02-15, 03:57 PM   #3  
If it's a heat loss problem, there are other things to consider such as the windows. Is there an attic? There are too many places to loose heat to focus just on wall insulation. R13 goes in the walls. R19 is too thick. If I were to replace what's there, I certainly wouldn't put the old insulation back in the walls again.

 
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06-03-15, 07:41 PM   #4  
I just replaced the windows....got extra insulation up in the attic and just taking advantage of opportunity that my friend offered to help me with spackling....current old drywall is only 3/8...so I would also "upgrade" to 1/2inch.

Upon closer inspection the existing insulation is R9 and I would do it for every wall that is facing to the outside....which actually isn't that bad since on the other side of my house there is garage and the LR is mostly bay window and entrance so it really would required about 10 sheets of 4x12 panels

 
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06-03-15, 08:30 PM   #5  
Ok. Your best bang for the buck would probably be to go with Roxul insulation, like this. It's about $0.75 per sq ft. Judging by your drywall sq ft, that would be about $360. But you would also want to insulate the garage wall.

 
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06-04-15, 05:10 AM   #6  
As far as the 3/8 dry wall goes, keep in mind that the difference between that & 1/2" is only 1/8". I wouldn't replace any 3/8" dry wall just for the sake of an "upgrade". I would only install 1/2" in the areas where the 3/8" had to be removed.

 
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06-04-15, 04:54 PM   #7  
Correction to my post above about existing insulation....it actually doesn't have any rating.... seems original to the house (1964) and simply says Corning Fiberglass 1 1/2 inch Economy.
Has gray paper as the vapor barrier.

I think 1.5 inch thickness would translate to R9 ??

Xsleeper - I previously used Roxul Sound insulation.... seemed easy to work with but don't think they have vapor barrier - is that something to worry about ??)
Also ...what is the R value for the Roxul Sound insulation ?
Would love to make at least my bedroom warm AND quiet

 
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06-04-15, 06:34 PM   #8  
Several varieties of Roxul do not have an R-rating. Those intended primarily as sound or fire insulation are significantly denser than the ones for thermal insulation and that may compromise the thermal insulative properties.

 
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06-04-15, 07:59 PM   #9  
Furd beat me to it. Regarding the vapor barrier, watch the video in the earlier link. It shows a vapor barrier can be added after the insulation is installed.

Comfort batt is the type of Roxul you should use in an exterior wall and their web site tells you so. The sound batt is only for interior walls, floors and ceilings.

 
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06-05-15, 06:03 PM   #10  
by the way.... as I am taking down the old insulation....it looks OK as far as inch and a half insulation goes..... any ideas for future use or recycling or should it go straight to garbage?

 
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06-05-15, 06:29 PM   #11  
Garbage......................................

 
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06-06-15, 03:33 AM   #12  
As you remove that 1964 fiberglass be sure to wear a mask, gloves, and long sleeve shirt. Old fiberglass insulation was noted for its irritating properties.

Bud

 
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