Use Of Vapor Barrier's In Basements

nywoodwizard

I've been reading lately about vapor barriers in basements and its amazing how many different opinions/information there is on this subject. Is it possible an industry this big is absolutely clueless? If you know of specific reasons to contradict this article then lets here them. No "i think", hard data only . You may state codes from your local jurisdiction.

I found this article on Wikipedia from buildingscience.com.
ICAA Technical Bulletin re vapor retarders "it is recommended that a vapor retarder not be used in a wall that is partially or fully below grade."]
Vapor Barriers have become controversial and some out of date building codes may still require their use resulting in moldy basements. Current Building Science recommendations is to limit vapor barrier/retarder usage to limited circumstances. See sources in references.
Use of vapor barriers in basement is especially not recommended.

http://www.buildingscience.com fully explains the use of vapor barriers in basements

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Learning without thought is labor lost; thought without learning is perilous.

kevjob

irc 2003 all exterior walls including basements shall be insulated with a vapor retarder, exclusions are shower walls use unfaced. Denver codes

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Kevin
Basement Finishing Highlands Ranch Colorado
Littleton Colorado, Basement Remodeling
Kitchen Remodeling Denver

concretemasonry

The flow of moisture it totally different above grade than it is below grade, but often people try to take the simplistic and easy approach for both applications, which is not always best.

Years ago, i passed off the Building Science concepts, but after reading closely and looking at them in comparison to what really works, I see they really do make sense. - At least they know enough to know how a vapor retarder works below grade and that there really is no such thing as an absolute vapor barrier.

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Dick

Engineer, designer and consultant recently active domestically and internationally on construction and design in about 35 countries.

kdrose27

Thats wikipedia for ya...........The most worthless source of information you could possibly use. Any Retard can post information on wikipedia without knowing anything about the subject only opinions. NEVER USE WIKIPEDIA thats if you want credible information anyway

kdrose27

I agree there is no 100% vapor barrier. But we all should be cautious and apply anyway.........Vapor barrier=$$$

nywoodwizard

Is wikipedia the only word you read ? Did you read the source? It wasn't wikipedia it was http://www.buildingscience.com. Absorb what you read before you post, we already know what wikipedia is about.

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Learning without thought is labor lost; thought without learning is perilous.

Pavola

Good links there. The most important part though, I think, is finding a way to allow for drying because it makes sense that if you need a moisture barrier then you have a need for drying as well. This reality hit the fan today when I tore into a chimney chase and found the whole thing was rotted. Built 12 years ago. HO had existing house wrap with T&G siding originally and then 2 years ago installed another layer of house wrap, 1/2" foam, and vinyl siding. Those layers effectively caused a vapor trap, no possible way to dry, and everthing was shot, including the studs, bond, joists, etc. This had Tyvek brand wrap, which I've always thought it is to tight, and it was like powder. I've done a water test on many of these house wraps and alot of them hold water for much longer than you would think. And I figure if water can't pass through, how the heck is air gonna get through.
I do think vapor barriers are necessary in many situations, but in others they can cause problems, so each climate needs its own specific one, not one that's a "national code".

Milhaus

I remodeled a basement this last spring, and based my approach off of buildingscience.com info as well. Great site. The one thing I've realized this past year is that this industry is learning right along with every other one. I agree with the basement theory, no vapor barrier below grade.

I've since seen spray foam used and haven't formed my own opinion as to whether or not open or closed cell is the way to go. I've seen some foam pulled off a brand new house and between the foam and the wall the tiniest air gap was there full of mold. Another question to be answered.

Mark

nywoodwizard

I'm in the middle of a basement remodel now and I'm still undecided on the methods i should use. I do believe there are lots of building codes out of date,and this may be one of them.

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Learning without thought is labor lost; thought without learning is perilous.