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How to finish Roxul sound-proof insulation in my basement


PaulSC's Avatar
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01-10-15, 07:32 AM   #1  
How to finish Roxul sound-proof insulation in my basement

Bought a place in NJ....built in the late 60s
I have large basement that is poured concrete - and I plan to turn it into an ent. room on one side and a laundry / workshop on the other half.
Did put up a dividing wall and filled it with Roxul sound/Fireproof insulation.
I have also filled the ceiling of my basement with the same stuff to insulate from the noise.

I have two questions:
1. Would it make sense to add thermal insulation on top of Roxul (which has very little R-value) to keep the cold air from penetrating through the flooring into the main living spaces ??

2. If not to no. 1, then do I need to put vapor barrier ? I do intend to install drop ceiling....or something similar.

Thanks !

 
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chandler's Avatar
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01-10-15, 07:53 AM   #2  
Don't know why you say Roxul has very little R value. For 3 1/2" it is a R15, whereas fiberglas is only R13. Roxul will need no support on vertical surfaces, but as with any insulation you will need to support it in the ceiling via stay wires. I would not bother adding any insulation to the roxul since it fits so tightly. It also requires no vapor barrier.

 
Bud9051's Avatar
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01-10-15, 09:06 AM   #3  
If your Roxul is the "Safe 'n' sound" that I see in 3" thickness it does have a typical r-3.5 per inch value, (my estimate). If it is very thin, then it would have a lower r-value, but also less of a sound benefit.

Before you close up that ceiling be sure to air seal and insulate the perimeter of the basement ceiling, the rim joist cavity, as that is where the cold is leaking in.

Bud

 
PaulSC's Avatar
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01-10-15, 05:16 PM   #4  
Safe'n Sound - that's the one.....pretty sure it is 3inches

thanks!

 
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