[Cob] light straw density and R-value

[Brad Calvert]

>The data you quoted for #s per cu ft seems way too heavy to me.  Robert
LaPorte's figure is 35-45 #s/cu ft.

I figure 40 #s/cu ft is about 650kg / cu metre

Here people mostly give densities as multiples of water density, so light
straw is about 0.65

I think concrete is about 2.5, I suppose solid clay is about the same.

There is aerated concrete that is full of bubbles from aluminium powder than
reats and makes hydrogen bubbles in the concrete.  There must be data about
the density and R-value of that compared to normal concrete.

I wonder if it is reasonable to assume light straw of a similar density
might have similar R-value to aerated concrete.