Vapor Barriers

[buckofdurham]

I thought vapor barriers in crawl spaces only had to cover %80.
A home inspector said it has been changed to a %100.
Any body know the facts.

[Hube]

If it's only covered 80 %, then there is bound to be a 20 % leakage. That's why any vapor barrier that is installed should have all the seams/joints lapped and taped.

[buckofdurham]

If it's only covered 80 %, then there is bound to be a 20 % leakage. That's why any vapor barrier that is installed should have all the seams/joints lapped and taped.

That sounds like a sealed crawl space. With them taped.
I have noticed with %100 of it sealed that it will contain wetness in the dirt. Under a house in a low area.
I was wondering the exact building code. I had "heard" %80 was code compliant.

[Hube]

Codes vary all over North America. What State of the U.S. or what Province of Canada are you in?
And are you meaning "moisture barrier" or "vapor barrier, there is a difference.

[buckofdurham]

Codes vary all over North America. What State of the U.S. or what Province of Canada are you in?
And are you meaning "moisture barrier" or "vapor barrier, there is a difference.

I'm in North Carolina. I didn't know if General Contractors had a national code or not. I think all the other trades do. Of course all jurisdictions don't adopt the code. So your right every place is different.

I've only heard the plastic under the house called a vapor barrier.
I have seen some sealed crawl spaces where they used that white stuff. It looks like it has string fibers in it. Then on the walls they would use 3/4" sheets of foam all sealed together. Is that a moisture barrier?

But what I am talking about is 6mil clear plastic.
Thanks for the feed back
Buck

[pushkins]

North Carolina requires a 100% covered crawlspace with 6 mil. plastic, the plastic must be held in place and doesn't have to be taped but in all cases should be overlapped.
Most building inspectors will look for coverage to be uniform, in other words they don't want to see a 1' section of plastic missing from one side of a dwelling.

[buckofdurham]

North Carolina requires a 100% covered crawlspace with 6 mil. plastic, the plastic must be held in place and doesn't have to be taped but in all cases should be overlapped.
Most building inspectors will look for coverage to be uniform, in other words they don't want to see a 1' section of plastic missing from one side of a dwelling.

Thanks !.............