[Cob] Lava Rock

[Janet Standeford]

Shannon is right about one thing,
I should have said the word "effective" as in: The correct statement 
would be that for the house design and location, the cob building from 
Arizona has an effective r-value of 19 for 20 inches.

That doesn't mean the effective R Value is inaccurate or misleading. If 
anyone builds green and sustainably and with an eye to the placement and 
direction the house faces, they could achieve this effective R value 
with the same type of soil and mix.