[Greenbuilding] Earth block wall section

[tom]

It seems to me that PU up against adobe is a bad idea as the adobe  
has the ability to take in and to give off moisture, basically  
allowing it to slowly migrate in and out from wetter side to dryer  
side seeking equalization.  I think PU is practically waterproof, so  
putting it against the adobe will stop any moisture migration on that  
side, possibly allowing moisture to build up.  Seems like a more  
'natural' insulation with at least some ability to also allow  
moisture to pass would make more sense.