[Cob] Insulative values

[Christopher Reinhart]

Damon wrote:

> Although blind faith is bad and challenging bad policy is good, changing
> for the sake of changing is naive.


Agreed. I didn't mean to promote change for change's sake. I just think
that the rationale of doing something just because that's the way it has
always been done is a weak argument. Tarp mixing is an innovation. Balecob
is an innovation. So is tractor mixing, rototiller mixing, and on and on...

Damon wrote:

> Building practices have been honed over generations, so we're not
> reinventing the wheel. Enough research has been done to show insulative
> values of cob are sadly low. I have read that the best approach to
> designing with insulation is thermal mass on the inside to act as a
> temperature regulator and insulation on the outside. BUT the problems with
> this approach is the cob can't breathe, so it can't dry out which will
> cause 1. the wall to eventually collapse, 2. mold, 3. a lot more woodwork
> for framing. You'd need to build an air gap in between the walls and that
> gets into a lot of extra work and know-how.


If the insulation on the outside is straw bales then the cob can still
breathe. The few times I have seen people combine cob with conventional
materials, the results have not been exemplary and they have experienced
the mold problem you refer to. I have personally used cob in combination
with straw bale and slipstraw and the results have been wonderful. When I
have visited or worked on other hybrid natural homes in the midwest, my
observations have been the same.

-Chris Reinhart