Vapor Barrier Required beneath flooring?

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  #1  
Old 02-23-07, 06:51 AM
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Vapor Barrier Required beneath flooring?

Hi I've got a 9X13 Breezway room w/an unaccessable crawlspace foundation. I'm removing some of the subfloor and want to know if I should install poly vapor barrier under the hardwood floor I'm going to put down in that room.
THere was previously linoleum tile w/no barrier beneath but not sure if I need one here? The room is heated and abutts the garage on one side (that wall has a 6mil barrier) and the other side of the room is opened up to the kitchen.
Any help is greatly appreciated.
jay
 
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  #2  
Old 02-23-07, 08:43 PM
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You want to put down a 6 mil poly on the ground there for sure. Over lap it by 2 ft and tape all seams. Put a R19 in each joist space paper to teh crawl space up on the sill plate all around the home there.
 
  #3  
Old 02-24-07, 08:12 PM
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No access to joists.

THanks,
But I had not intended on removing all the subfloor to expose the joists. I'd really like to know if it makes sense to put the poly barrier beneath the hardwood or engineered wood floor. Or perhaps the 1/4 subfloor I'm adding to the existing before putting down the finished floor.

The area in the crawlspace is enlcosed by it's foundation an inaccessable.
 
  #4  
Old 02-24-07, 08:25 PM
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For sure cover the ground there with the 6 mil poly also
 
  #5  
Old 02-25-07, 06:23 AM
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I'd suggest you ask your question in the forum for wood flooring. I would assume that your floor is already insulated, perhaps with kraft facing (a vapor barrier). Since you mentioned that your crawlspace is inaccessable, I suppose that would be hard to discern. Wood floors are often laid on top of #15 felt, which itself does not qualify as a vapor barrier, but it does reduce the transfer of some moisture from below. I've never heard of putting a poly vapor barrier between layers of subfloor. If it worked, you'd get moisture against the poly and wet the subfloor below the poly. A bad idea for sure.
 
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