Can I add plastic on top of the insualtion


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Old 06-10-14, 09:43 PM
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Can I add plastic on top of the insualtion

I am adding insulation to a previously unfinished attic space next to my bedroom.

The only insulation that was there before was an old, ugly unfaced bats on the wall between the bedroom and the space. I replaced that insulation with R13 and applied additional R13 on top of it only turned it around i.e. face to the studs, hoping for better R value???
Can/should I put a vapor barrier on top of that (now unfaced) insulation or is it going to cause more problems than bring any benefit?

Thank you,
 
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Old 06-11-14, 03:06 AM
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Any vapor barrier you have, including faced insulation should go against the living area. You do not want to apply another vapor barrier on top of existing insulation. Why only R13? Your attic should have at least R29.
 
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Old 06-11-14, 06:49 PM
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Thank you Chandler!

Here is a sketch drawing to better show what I have.
There is no room for R29 in that wall separating the "attic" space and the bedroom, just 2x4 studs, so I was able to find only R13 that fits in there.

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following are the pictures of that wall separating the bedroom and the "attic" space.

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view at the rafters going through that "attic" space

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this is the outside wall from the same space

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Old 06-12-14, 03:04 AM
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OK you were insulating a wall. R13 is about all you can get in a 2x4 stud bay and still have it flush. Is that Roxul in the other bays? If so it is far superior to any fiberglas insulation. I would use that.
 
 

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