Cob: Cob insulation idea

[lightearth at onebox.com]

Yes, the big unknown of the system is the R value of the center insulation between the inner and outer Cob walls. I don't count on the outer wall being much in the way of insulation but is strong (aprox 5-6") and seals (breathable) and protects the center insulation of the 'sandwich'. I wish there was convenient ways to test the R value of the straw/clay panels or paper/clay panels that work as insulation for us but this type of wall doesn't really lend itself to the same type of design as a stud wall with fiberglass (typically) which I've often found leaks air through it in several places, has cold spots regularily and has lung-damaging fibers.

 The other interesting thing is how people typically react to these wall ideas re:vermin......No wall seems to attract mice quite like a 'stud frame' wall with it's many channels, light insulation and difficulty in sealing up with anything hard....the dense walls seem to be almost impenetrable to them if done right!

Marlin

lightearth at onebox.com wrote:
> 
> Hey Jen,
> 
> ....,,24 inches of dry wood doesn't present much of a thermal break.

It presents a thermal break of R-val 30.92 for white pine to 31.44 for
spruce or yellow pine.  What does your clay panel R-value per inch?


> We plaster over the whole thing
I though you were putting it between walls.

.. ending up with about a 24 inch wall with thermal mass, insulation (R
value?) and a durable/load bearing wall...
> 
The mass is already there in the cob, it has its own R-value as well.  
Which might not be necessary depending on the area.   For areas with
long cold spells and little sunlight energy this would be good. Earth
does not conduct heat quickly, but it can store and sink a lot.

> Marlin
> --

Darel