Cob: RE: RE: Re: INSULATION FACTS

[Michael Saunby]

On 19 July 1999 22:29, John Schinnerer 
[SMTP:John-Schinnerer at data-dimensions.com] wrote:
[SNIP]
> Focusing on the R-value of cob is to me silly, because cob is not 
primarily
> an insulative material, it is primarily a thermal mass material.  In
> locations where thermal mass alone will not "work" for whatever reasons
> (lack of sun for passive solar, not wanting to run a woodstove all 
winter,
> etc. etc.) cob alone will not work - and it may or may not be useful as 
part
> of a structure, depending on how and where it is used.

That's not really true either.  It's fair to say that cob has high thermal 
mass, but it is primarily a construction material used for the external 
walls of buildings.  It has been used as such for centuries, ancient cob 
buildings make little or no use of cob internally (it would be wasteful of 
space, and possibly effort and maybe materials - though evidence is that 
internal walls used more expensive/scarce materials).  There is no evidence 
from any old books or decriptions I have seen of building techniques, 
choices of materials, or living conditions prior to this century that 
insulation, or thermal mass of buildings was ever an issue.

Various folks have at times on this list suggested internal thermal mass 
structures to hold heat in their house, either using cob for internal walls 
or insulating the outside of a cob house.  Whilst there is no reason I can 
see that this won't work, there's no precedent for it either.  To my mind 
if you just want a large thermal mass inside your house it makes no sense 
wasting space with the relatively low thermal mass of dry soil when you 
could get a a few crushed motor vehicles and put them in your living room, 
or use heavy cast iron heating equipment.

Michael Saunby