[Greenbuilding] [BULK] Re: thermal bridging--letting it go

[Lawrence Lile]

>  If we have 1" of foam, we don't need no stinking Tyvek!
    Clarke Olsen

Maybe so, my salty-toungued friend, however I see Tyvek as a very cheap addition to the tighhtness of a house.  If you install the foam with gaps at the joints, per mfr's instructions, then the tyvek will serve to stop infultraition at those gaps.  If you install it tight, then maybe it is superfluous, or as you say "we don't need no stinkin'"  
 
Foam would serve as a drainage plane, except as I see it horizontal joints might allow bulk moisture to run into the wall.  One of the key functions of tyvek, besides infultration, is a drainage plane.  
 
--Lawrence Lile
"we don't need to stinkin' oil imports"