Regarding VBs on/in walls – there was an excellent article by Joe Lstiburek which addressed this issue in a very succinct manner. I believe it is copy-righted material, and so I can’t supply it here, but it was in the February 2002 ASHRAE Journal (pp. 36-41) as part of the “Moisture Control Series.” It is one of the best discussions on the matter I have seen.

Dr. Lstiburek breaks down the country into climatological regions, and in the context of those regions explains when a VB is appropriate, and explains where the VB should be installed.


My post above references Dr. Lstiburek. Lots of good info on that web site.

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Dave