Cob: Cob insulation idea -Cob Scrap

[Darel Henman]

Marlin,

Some advice to help get your message across better it to not don't use
the phrase, "insulation break".  It causes confusion, at least for me. 
I think what you are trying to say is an "insulation layer" between cob
walls, or a insulation between conduction paths.  Also insulation does
not "break" off conduction, it still conducts, but only less.   One
reader though you meant thermal bridge, which is quite the opposite of
what you meant. 

> The insulation 'break' between the inner and outer walls is pretty important here - long, cold, gray winters sometimes..... but the mass on the inside helps to modify the temps....also think thermal mass is really good in floors esp. if radiant.
> 
> Marlin


Now about figuring a R-value for your product.  Once is to have a
laboratory that does this, do it for you.  Perhaps some engineering
school nearby.   

Another way to estimate what it should be is to take the R-value per
inch of each materail used then use the percentage each of these
materials and calculate a weighted average.  This would give you an
idea.  

One thing to also remember, however, is that R-values can be misleading.
Here's an interesting article called the "R-Value Fairy Tale" that you
might enjoy.

http://www.monolithicdome.com/plan_design/rfairy/


Regards,
   Darel