[Greenbuilding] Earth block wall section

[Alan Abrams]

> My concerns are the spray foam and adobe together. I'm a bit hesitant  
> on that combination. But I don't  know how well the two materials  
> will play together. His other questions are minor to the fact of  
> whether this wall system would actually function in a varied climate  
> such as ours.
>   

>>>>>>>
I think CEB's can be compacted a lot more than adobes. That may or may 
not have an  impact on how the foam works with or against the earth, and 
I haven't run across and tests in English discussing how the more 
compressed blocks absorb moisture.  As long as the block withstands 300 
pounds psi, it can be used as if it were loadbearing masonry. IIRC, some 
of the CEB's exceed 3,000 psi. Maybe even more.
As for the foam...perhaps placing a 1/2" layer of rigid foam insul 
between the earthen blocks and the foam would be worth considering.
<<<<<<<

The rigid foam is a good idea; not only to eliminate any problem with
potential incompatibility with the materials, or any moisture transmission
issues, but also to allow for the inevitable differential movement between
the frame and earth walls.  OTOH, the proposed 4" section of earth wall
sounds a wee bit slender for bearing, even with high values for compressive
strength.  Single story, unstabilized adobe is ok for loads at 10" wide,
dunno how that would translate to compressed blocks, or at what point it
would be practical to swap out the post and beam and infill concept.  

-Alan Abrams