Cob: vermiculite

[Answ999 at aol.com]

Vermiculite   has been used alone for a poured in insulation in stick built 
homes (fills the gaps left around the edges of fiberglass or rock wool) or in 
place of the fiberglas.  The dust is classified by the EPA as non toxic.  
particles are too big to be the problem fiberglass and asbestos have been for 
the lungs.  All you need is a common dust mask.  Has been used in potting 
soil to hold air.  Has been used on concrete as a way to lighten the weight 
without weakening the concrete itself and it traps lots of air to provide 
insulation  (like R Value increase)   It has been in use with concrete for 
decades so the engineering has been done.  My guess is it could work much the 
same way with COB, lighten it without weakening it, and offer much needed 
resistance to the thermal transfer of heat or cold.
Lyle