Thread: 2009 N1102.2.9

We are just now going over to the 2009 IRC around here, & I'm seeing that in N1102.2.9 that a vapor retarder is only being required in unvented crawlspace foundations instead of all crawlspace foundations like it was in the 2003 N1102.1.7. I can see this as being an issue & would like to get some input or just see if I might be missing something.

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Better take a closer look........2003 N1102.1.7 states uninsulated floor and unvented crawlspace....then a vapor retarder is needed.....not all as implied...

It doesn't say that, it says, "The exposed earth in all crawl space foundations shall be covered..."

I was referring to your reference to the 2003 code.....that's all

Originally Posted by John Goad

We are just now going over to the 2009 IRC around here, & I'm seeing that in N1102.2.9 that a vapor retarder is only being required in unvented crawlspace foundations instead of all crawlspace foundations like it was in the 2003 N1102.1.7. I can see this as being an issue & would like to get some input or just see if I might be missing something.

Don't think you are missing anything however if the vapor barrier is installed in the vented crawl space the the ventilation requirements can be reduced to 1sq.ft opening per 1500 sq feet of floor area instead of 1 per 150 sq feet of floor area. for this reason alone it is apparent it is helpfull in reducing the need for ventilation (controlling moisture) so we require it regardless. But if someone refused to use it in a vented crawl space, it appears it would be acceptable as long as they had the required ventilation.