[Greenbuilding] Adobe mix

Alan Abrams alan at abramsdesignbuild.com
Fri Jul 6 09:36:40 EDT 2007


<All answers YES, except double story design means some walls will get rain
during our wet winter months.  I'm planning to plaster with a lime/cob mix
and wonder if this finish will sufficiently protect the integrity of the
walls?>


hmmm, what I was familiar with in the American southwest was one of two
approaches--

the first was the traditional, based on the practice of the Pueblo Indians,
in which the adobe walls were plastered by hand with the adobe soil and
straw mix.  Head joints in the bond were left un-mortared to provide a key.
The coating was exposed to rain (avg 10" / yr), and refreshed periodically.

The alternate was to wrap the walls with stucco netting (20 ga 1 1/2" hex,
furred out about 1/4") and plaster it with 3 coats of Portland/lime/sand
mix.  The ferro cement cladding was robust--I can recall seeing abandoned
houses with collapsing roofs, and the adobe bricks melted away--and the thin
stucco shell still supporting what remained of the roof.

Sounds like the lime based cob would occupy a middle ground in this, OTOH,
severe weather would still take somewhat of a toll, particularly if the cob
is subject to frost action.

Nonetheless, what this suggests is that maybe it's ok that organic methods
might lack some absolute degree of "integrity;" that maybe it's ok that a
house would require some regular maintenance.  It's as though such houses
are living organisms, which like our own bodies, need to be nourished and
groomed from time to time...

-Alan Abrams  



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