Cob Earthen History Revisited

[Paul & Mary Salas]

John, Jeffrey and others,

This is in response to "Cob Code" and "Cob Failures"

It has been stated many, many times, building with earth is not new and
its properties are well documented although now well published.  When we
view earth construction as a whole, we must place Rammed Earth, Cob,
Adobe and even Wattle and Daub into the same category--similar to when
we speak of concrete.  The elements are similar and the variance is in
the mix design and the admixtures that enhance the performance features
being sought.

There has been extensive writing, data collection and publication on
earthen construction in the U.S. with a wide geographical distribution
in location,. architectural style and construction technique.  The
oldest known publication in the U.S. having to do with earth
construction is by S.W. Johnson, "Rural Economy", 1806, "Economical
Builder, "A Trestie on Tapia and Pise Walls", 1839 by E. Gillman.  In
1873, the U.S. Quartermaster Department published "Notes on Building
with Concrete and Pise" for use in constructing military structures.

If you can find a copy of the 1927 U.S. Department of Agriculture,
Farmer's Bulletin #1500: "Rammed Earth Walls for Buildings" by T.A.H.
Miller and M.C. Betts you'll see why this was the bible for earthen
construction during the 1920's, 30's and 40's.  The U.S. Department of
Agriculture played a lead role in promoting earth construction with
extensive documentation.  In 1926, T.A.H. Miller published a report on
the condition of earth buildings for the period of 1820-1854.  Ralph L.
Patty published data on his work on the Indian Reservations in the South
Dakota along with finishes for the interior and exterior and, puddled
earth in 1939..  Thomas Hibben published a living history of earth
homes, churches and commercial structures in Alabama including
discussion on those that had survived earth quakes.  Interesting note,
the failed component in these structures was the unforgiving concrete
that had been added to the buildings after completion.

For those interested in pursing data collection, I suggest that you
start with the book "The Rammed-Earth House" by Anthony F. Merrill,
1947.  Don't confuse this with David Easton's 1996 publication by the
same name.  It's a good reference source.

I believe the historical data as well as test data are already
available--they just need to be updated.  For example,  the Extracts of
the 1939 ASTM Standards includes discussion for earth construction as
did the 1941 Kansas Experiment Station Bulletin No. 41 by Charles
Fenton, "The Use of Earth as building material".

I hope this puts to rest some of the frustration about
Cob-Pise-Adobe-Earth construction not having been studied and that there
is no data----this oughta to keep a few of you out late at the library
for a while.

Paul Salas
SANCO Enterprises
Albuq., N.M