Can I add plastic on top of the insualtion


  #1  
Old 06-10-14, 09:43 PM
N
Member
Thread Starter
Join Date: Oct 2003
Location: San Diego
Posts: 641
Upvotes: 0
Received 1 Upvote on 1 Post
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,
 
  #2  
Old 06-11-14, 03:06 AM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 36,608
Upvotes: 0
Received 9 Upvotes on 8 Posts
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.
 
  #3  
Old 06-11-14, 06:49 PM
N
Member
Thread Starter
Join Date: Oct 2003
Location: San Diego
Posts: 641
Upvotes: 0
Received 1 Upvote on 1 Post
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.

Name:  IMG_20140611_183159.jpg
Views: 93
Size:  27.4 KB
following are the pictures of that wall separating the bedroom and the "attic" space.

Name:  IMG_20131125_095131.jpg
Views: 136
Size:  36.7 KBName:  IMG_20131125_095137.jpg
Views: 87
Size:  32.5 KB

view at the rafters going through that "attic" space

Name:  IMG_20131125_095144.jpg
Views: 108
Size:  35.0 KBName:  IMG_20131125_095156.jpg
Views: 81
Size:  35.1 KB

this is the outside wall from the same space

Name:  IMG_20131125_095206.jpg
Views: 87
Size:  31.4 KB
 
  #4  
Old 06-12-14, 03:04 AM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 36,608
Upvotes: 0
Received 9 Upvotes on 8 Posts
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.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: