MyFloridaCode.com

In a wall yes - unfaced insulation can be used in Florida.  On the 
underside of a roof deck only air impermeable insulation can be used. 
A faced batt is not air impermeable.  Low density and high density 
spray foam are air impermeable.

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>So what I'm hearing from you guys is that we don't even have to use 
>the faced batt insulation?  Obviously, the advantage of using the 
>faced is the ability to use it to hold the insulation in place.
>
>From: codetalk-bounces at myfloridacode.com 
>[mailto:codetalk-bounces at myfloridacode.com] On Behalf Of Mark Cramer
>Sent: Saturday, February 06, 2010 2:40 PM
>To: codetalk at myfloridacode.com
>Subject: [Florida Code Talk] Vapor Barrier
>
>What Dr. Joe said.
>
>You don't need a vapor barrier in cooling climates. You really don't 
>want one. If you did install one, you would want it on the exterior 
>(warm) side of the insulation.
>
>In our climate, water vapor will move in both directions (to the 
>interior and to the exterior) at different times of the year. The 
>difference in vapor pressure and temperature is not as great in our 
>climate as it is in extreme heating climates, so we typically don't 
>have the same issue with condensation as you would get in a very 
>cold climate. Better to let the vapor move through the wall in 
>whatever direction it wants, and make sure the wall can dry out.
>
>The biggest mistake I see contractors make in our market is the use 
>of foil faced foam insulation boards on the interior of concrete 
>block walls. This causes vapor moving from the wetter exterior to 
>the drier interior to condense on the exterior side of the foam 
>board (inside the wall assembly) where it creates conditions 
>conducive to mold growth. Better to use an unfaced board with a high 
>perm rating and let the vapor dry to the interior.
>
>In Northern climates where they do need a vapor barrier and are 
>using spray foam insulation, I've heard that they spray a layer of 
>closed cell foam to provide the vapor retarder/barrier then spray 
>open cell foam.
>
>Mark Cramer
>Mark Cramer Inspection Services, Inc.
>492 20th Ave.
>Indian Rocks Beach, FL 33785
>727-595-4211
>http://www.BestTampaInspector.com
>
>From: codetalk-bounces at myfloridacode.com 
>[mailto:codetalk-bounces at myfloridacode.com] On Behalf Of Ken Rodgers
>Sent: Saturday, February 06, 2010 2:01 PM
>To: codetalk at myfloridacode.com
>Subject: [Florida Code Talk] Vapor Barrier
>
>Can someone give me the code reference for interior vapor barrier 
>requirements over insulation.  I'm specifically trying to find the 
>requirement (if any) for a vapor barrier over open cell foam.  The 
>research I've done seems to indicate the need for a vapor barrier 
>over open cell but there seem to be a few other opinions out there 
>as well with regards to our part of the country.  Just wondering if 
>the code addresses this specific situation.  I'm sure this question 
>will also spark a good foam vs. anti-foam debate so I look forward 
>to learning from that as well.
>
>Thanks
>
>Ken
>
>
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