# No requirement for vapor barrier in crawlspace?



## Coder (Jan 15, 2013)

Been scratching my head and the code books hard on this one. Can't find anything in the 2009 IECC or IBC that states a vapor barrier is required over the dirt in a passive vented crawlspace (crawlspace with foundation vents) of a commercial building. Am I missing something? Any input is appreciated. Eric


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## mtlogcabin (Jan 15, 2013)

Not required but a vapor barrier makes a big difference in the amount of ventilation required

1203.3.1 Openings for under-floor ventilation.

The minimum net area of ventilation openings shall not be less than 1 square foot for each 150 square feet (0.67 m2 for each 100 m2) of crawl-space area

1203.3.2 Exceptions.

The following are exceptions to Sections 1203.3 and 1203.3.1:

2. The total area of ventilation openings is permitted to be reduced to 1/1,500 of the under-floor area where the ground surface is covered with a Class I vapor retarder material and the required openings are placed so as to provide cross ventilation of the space. The installation of operable louvers shall not be prohibited.


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## lunatick (Jan 15, 2013)

There are vapor barrier requirements and then there are Radon barrier requirements.

Is CO concerned with Radon?


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## Coder (Jan 16, 2013)

Not a requirement. a concern yes but..We have adopted Appendix F in the 2009 IRC but the radon control measures in this appendix do not pertain to commercial buildings. Doesn't make a whole lot of sense to me. Has something to do with the amount of time a home is occupied versus say a school building, office, etc. I would like to see radon control techniques implemented in ALL new construction.


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## Coder (May 29, 2013)

Mr.Inspector said:
			
		

> Not a requirement. a concern yes but..We have adopted Appendix F in the 2009 IRC but the radon control measures in this appendix do not pertain to commercial buildings. Doesn't make a whole lot of sense to me. Has something to do with the amount of time a home is occupied versus say a school building, office, etc. I would like to see radon control techniques implemented in ALL new construction.


Could anyone out there confirm for me that Radon control measures are only called out in Appenndix F in the IRC and not anywhere in the IBC? Thanks. ie: optional in commercial buildings?


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## fatboy (May 29, 2013)

You are correct, not in the IBC.


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## Coder (May 29, 2013)

I thought so as well. Sometimes I need to hear it from someone else smarter than me. Thanks for the quick reply!


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## fatboy (May 29, 2013)

No problem.....don't know about the "smarter" thing. You knew it, I just was helping you through it!


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## Sifu (May 29, 2013)

I just spent 5 days in CO looking for property (and potential places of employment) and never ran across Frigidville.  Is there really a place or are you just cold?


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## Coder (May 29, 2013)

Sifu said:
			
		

> I just spent 5 days in CO looking for property (and potential places of employment) and never ran across Frigidville.  Is there really a place or are you just cold?


Cold and ruthless!    JK.. I actually am referring to Gunnison, CO in the wintertime. :devil


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## fatboy (May 29, 2013)

And it is the ice box of the state, trust me!


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