Cob: Re:apology re dumb & etc

[Otherfish at aol.com]

Sean & all others interested

Sorry if I irked, brused or annoyed when I called a double cob wall "dumb".
I did'nt mean to be unkind - just a combination of late Friday night & a 
testy mood.
How about: "A less than optimum solution".  Means kinda the same, just sounds 
nicer.
  
A wall constructed as:      | cob |  insulation  | cob |   ,would work real 
fine for insulation  if properly designed & built, so long as you don't mind 
( & back & feet & hands & LOTS & LOTS of mud ) building it.  Simply the point 
that I was wanting to make is that to build it would take MORE than TWICE the 
amount of cob  as it would take if you make it a single cob wall with some 
other form of insulation.
Thats all I wanted to say.
I realized that the double wall idea came from someone other than Sean ( 
don't recall who ) & did'nt mean to imply that Sean is in any way dumb ( nor 
the original suggestor either).  Sorry Sean if I came across that way.

Re: Sean's question of insulation vs air space vs how do double glazed 
windows work.   Double glazed windows have a vacuum between the two layers of 
glass.  A vacuum will transfer heat only by radiation.   An air space will 
transfer heat by convection & do so quite well & rapidly.  This is why 
uninsulated wood framed houses overheat and or cool so rapidly.  Air likes to 
move to temperature differences (wind) & just sucks the heat differential 
right along with it quite rapidly.  A double wall (cob or otherwise) with 
only air in between will set up convection currents in the air space & 
whatever one wall of the double cob is doing temperature wise , the other 
wall will do soon after.  At least that's my understanding of the dynamic. 

I can think of other structural issues that might be a problem in building a 
double cob wall if they are not addressed.  The most glaring is height versus 
width of the wall.  A cob wall will derive it's strength from is massive 
nature.  The historic adobe buildings in seismc active California which have 
survived earthquakes are those with a low height to thickness ratio (like 
somewhere around 3:1 or so ).  So it stands to reason that when building with 
cob you need to make your walls monolithicly thick.  To make a safe double 
wall will mean building two THICK walls.  Real massive !!!!  Two thinner cob 
walls with an insulation break in between can be potentiallly dangerous 
structurally.  This means double wide foundations, way wide lintels, way wide 
top of wall bond beam in seismic areas, tying the roof into two walls & 
probably more issues not immediatly apparent.  
So, do it if you want to, but my suggestion is look for a less probematic 
solution to insulating you cob structure.

Re the Cob Code & the real me.  Yes, this is the real me & the same bug 
infests me re the code issue.  To wit: the problem with the current code 
issue & a lot of the loose info flying around about how to properly build 
with cob is due to that we really don't know.  To try to fit cob into other 
models of construction smacks of silk purses & sow's ears.  For us cobbers to 
get a clear picture of the ACTUAL limits of cob & use this info to write a 
code that is base on the REALITY of COB means testing the material to find 
its limits.  Conjecture & theory are all fine, but they are just that.  Cob 
is cob & not sumpthin' else & until we really & quantifiably understand it, 
there is just too much guessing & reinventing of the wheel going on.
So, the status of THE COB CODE PROJECT ( TCCP ) is that it needs money.  I've 
done the initial program & developed a tentative budjet & schedule for the 
undertaking & it's MAJOR.  So, until I can find funding ($500K) & time (two 
years projected) - actually the $ will buy the time - well, the project is 
stuck in that particular limbo.  What it REALLY needs is a funding guru who 
wants to see it happen & who is willing to take an active role in making this 
CRITICAL $$$ next step happen.  I remain confident that it will happen - it 
must !!! - but at the same time, am continuing to breathe.

Thanks for your post & fire setting Sean.
Regards,
john fordice
TCCP
otherfish at aol.com