[Cob] Lava Rock

[Janet Standeford]

Are you saying theirs is true R value?

As for the energy model I know of, it passes muster with building 
officials as R value for my house.

The point I am making is that .5 for regular cob is a pretty low guess 
on their part versus the nearly "1" I will be getting. So it doesn't 
appear that the pumice actually adds anything to the equation when 
theirs comes out to "1" with the pumice.

Also Shannon, effective value or not, it was measured at 19 for 20 
inches. Yes, site, sun, etc have everything to do  with it but as cob 
will never have a true R value due to variances in the mix and soil, 
effective value is the closest thing we will ever get to measuring it.

So don't jump down my throat for going with what I can get in the way of 
a measurement just because I have an opinion on regular cob versus 
pumice cob and the claim made on their website regarding R value for 
regular cob!


> As I have explained previously, cob is NOT anywhere close to R19 for 
> 20 inches, your energy model is specific to your building and site.  I 
> believe the term used on your paperwork was "effective R-value" it is 
> not a generic design definition that can be used for other cob 
> installations. Effective R-value has a specific context and is only 
> meaningful in that context, it cannot be applied to other buildings 
> unless they have a similar design, latitude, sun-hours per day, and 
> probably other conditions.
>
> Shannon C. Dealy      |               DeaTech Research Inc.
> dealy at deatech.com     |          - Custom Software Development -
> Phone: (800) 467-5820 |          - Natural Building Instruction -
>    or: (541) 929-4089 |                  www.deatech.com
>