Vapor barrier??????

[jjcold]

Well, here's something that has me confused. What is the scoop on using vapor barriers? I live in the Pac Northwest, where it is generally mild throughout the year, avg winter temp 46 and avg summer temp 72 and not too humid. I don't believe my new house had any vapor barrier installed between the insulation and the sheetrock (warm side of the wall) unless they did it right before putting the sheetrock up, or used that special vapor barrier paint. After poking around, I'm not even sure if vapor barrier is a good thing or not. Does it cause more problems with mold? I leave the little vents on the windows open year round and always use the exhaust fan and open my kitchen and bathroom (both bathrooms have one!) windows when cooking or taking a shower. I don't think having or not having a vapor barrier is a big deal for me, but it's another one of those "why do some builders do it and others don't?" sort of thing.

[Rich]

I go to my standby at toolbase...
http://www.toolbase.org/Docs/MainNav/MoistureandLeaks/3950_weatherresistantbarriers.pdf?TrackID=&CategoryID=1017&DocumentID=3950

[jjcold]

Thank you, Rich, for the link. It did help me to better understand housewrap and building paper. However, I was referring to the interior poly sheeting that I read about installed on the interior side of the studs before drywalling. My builder did use building paper. Most builders around here use Tyvek or some other similar product, but I do see a few houses, and not always the cheapest ones, wrapped with builder's paper, too.

[Rich]

Huh.. I must have linked the wrong article.. let me find the right one. Missed it by 2 - http://www.toolbase.org/tertiaryT.asp?TrackID=&CategoryID=1017&DocumentID=4403
and here is also an interesting read
http://www.canadianarchitect.com/asf/enclosure_design_strategies/enclosure_strategies/enclosure_strategies.htm

[danh]

I'm gonna have to do a hardcore bling-out on this one.

2005 saw a fairly comprehensive code proposal submitted which would eliminate the need for vapor retarders in many jurisdictions. It didn't see much resistance in Cincinnati, excluding some arguments over whether or not Zone 4 would still need a vapor retarder.....

we should find out in September if it will be part of the code.

Vapor retarders are good at what they do, but that can be a problem. The new code package is to ensure that VDRs are only installed in places where they are absolutely necessary, like Canada.

See "Understanding Vapor Barriers": http://www.buildingscience.com/resources/articles/default.htm

jokes.