Cob: cob blocks?

[SANCO Enterprises, LLC]

Darel wrote

> Sensing some confusion due to terminology I'd like to say:

> For clarification:
> Adobe is not Cob.  Cob has much less moisture in the mix.  I'm not sure
> about any straw content differences.

Experiences in different parts of the world, especially with earthen
materials, leads one not to make rash judgments as to what something is or
isn't.

Here are a few examples;

1) Prior to the arrival of the Spanish in the new world, Native Americans
used a "puddled earth" method of construction.  Clay and straw mixed by hand
and laid free form, one layer upon another.  It is not cob?  Or is our
definition of cob one where the material has to originate in England or the
Northwest to be called  cob?  Is it the process or technique we are defining
and not the material, or is it both?

2) Darel also stated, > Cob material made into a block is fine, but it is
not adobe.  Adobe is a  very wet clay slurry that is sun dried before
application.   Adobe blocks would crack far more than a block of cob
material. >

Darel, this is a matter of who is making the adobes---adobe production yards
and those individuals using machinery do make a very wet adobe material,
with and without straw.  Mom and Pop builders don't make them wet---just
enough moisture to hand pat the material into the form--50 to 60 a day is
good.  Would not a truck load of cob material imported from the Northwest;
delivered to the Southwest; mixed and formed into blocks; would they not be
called adobe?

3) Our good friends, Bill and Athen Steen, made straw-clay blocks in
Obregon, MX that only contained enough clay to bind the material together
and definitely could not be poured.   It had to be packed by hand into the
form.  Is this cob with just extra straw or a poorly made adobe?  Or maybe
it is something else?

4) If forms are used and cob-like materials are used (clay-sand or
soil-straw) with a zero slump or less, and a concrete vibrator is used to
consolidate the material, what do we call the finished product?  It's not
adobe or rammed earth.  It has the properties of cob material, but it's not
cob.  The material has the consistency of puddled earth, but it wasn't laid
by hand and not free-formed. What do we call it--molded earthen cob?
Monolithic cob or monolithic adobe?

Every time someone tries to define an earthen construction process or
technique, a variant with the same material properties pops-up and
re-definitions start up again, or clarifications must be stated, or
exceptions noted.  I can almost feel the pain Rodney King felt when he said
"can't we all just get along?", when it comes to earthen construction.


SANCO Enterprises, LLC
Paul Salas, General Manager
P.O. Box 45741
Rio Rancho, NM  87174
(505)  238-1485
chansey at earthlink.net