[Cob] Lava Rock

[Shannon Dealy]

On Mon, 18 Jul 2011, Janet Standeford wrote:

[snip]
> Actually, they claim .5 R value for regular cob and 1 per inch for pumice cob 
> but actually the energy model done for regular cob is R19 for 20 inches so i 
> don't think the additional hassle of pumice really adds anything unless their 
> cob mix is vastly different.
[snip]

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 -
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