Cob: Re: Double Walls and insulation

[SANCO Enterprises <Paul & Mary Salas>]

"Shannon C. Dealy" wrote:

> I've been playing with this idea for a couple of years (though I haven't tried to
> build anything along these lines yet), and you have overlooked another
> possibility.  You could go with one thick structural wall on the support itself
> and enclose the outer insulation (it could even be lightly coupled to the
> structural wall for added strength).

Shannon, this is exactly the method I included in the USDA SBIR proposal I am
currently working on and the reason I as so intent on making a waterproof earth
render with just soil and no concrete.  We've crunched the numbers and it will
work.  I'm going to try cellulose with an wheat starch adhesive applied within a
frame and stand the insulation up as a panel then apply cob with the machine I
built for the purpose. There are many insulation possibilities, however we want to
be in the R-30 range plus the .25 per inch gained from the applied wall. The thick
earthen wall will go on the inside for the thermal mass and a thinner veneer on the
outside in the range of 4" to 6" thick.

I've stayed out of the insulation discussion because the issue being debated has
caused an awful lot of cost and frustration to builders in the northern areas of
New Mexico.  The choices are a double wall system (insulated or air space),
exterior sprayed on foam or mechanically attached exterior poly followed by a
stucco coating. If you don't comply, you don't build. I gave this insulated wall
system a lot of thought and when build full scale models and prove that the method
works, I believe we will be engaged in a new ball game with the code.

Paul Salas
SANCO Enterprises, LLC
Albuq. NM