Cob: breathing cob walls

Sat May 13 00:57:09 CDT 2000

I'm glad someone brought up the need for cob walls to breathe.  In New Mexico
the restorers had the bright idea of coating the outside of a very old adobe
church with mortar to protect it from the weather etc.  It almost destroyed it,
however.  Moisture that is in most all air entered the wall from the inside and
got trapped just under the mortar. Over the years it softened the clay in the
raw (unfired)  bricks.  Watertight sealants will gradually soften the clay
under them.  It may not show in a year but it will over time. 
 This church was in a quite dry climate near Santa Fe, New Mexico.  If you
would like more details I will look up the recent Smithsonian article and put
the page and issue on this net.

IT IS DANGEROUS TO TRY TO SEAL AN ADOBE OR COB WALL.  THEY NEED TO BREATHE.

Potassium silicate, I believe is a sealants that can cause this gradual
deterioration of unfired clay walls.    You may be undermining your building. 
Just what potassium silicate would do to garden walls is another question. 
Perhaps they would make the wall last longer than an unprotected  rain drenched
wall.  Much better are the ideas of putting a roof on the wall with an overhang
and putting stones in it that stick out.  Even terracotta (cooked earth) tiles
that are not glazed, just low fired, would be good protection even though they
are a little porous.  Most of the rain would run off.  If the wall breathed the
little moisture that went through into the wall would likely work its way to
the sides and evaporate.

What is important to remember is that even inanimate things are dynamic,
changing slowly or fast depending on the climate.  In the Egyptian desert they
can last for thousands of years but there are few places  that dry in the
world.  Even the ancient hieroglyphics thousands of years old, when inclosed
and viewed by too many  tourists can be destroyed by the moisture evaporating
from their bodies.  So we have to bend with the weather and the impacts of
changing climates and recognize that every move we make impacts the world of
future generations.  Acid rain, thanks to our  blind use of technology, is
decaying even stone monuments that lasted thousands of years.  The automobiles
in Athens are destroying the ancient Athenian buildings, for example.

Americans look for quick fixes.  When they are efforts to short cut natural
processes they always backfire.  Cob is great because it is mostly a product of
nature and when properly used and cared for can last for ages.  Tune into it
and it will give you a singing house.  Try to defeat the natural process and
they will let you down, or let the roof down on your heads.

Bob 

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I'm glad someone brought up the need for cob walls to breathe.  In
New Mexico the restorers had the bright idea of coating the outside of a
very old adobe church with mortar to protect it from the weather
etc.  It almost destroyed it, however.  Moisture that is in
most all air entered the wall from the inside and got trapped just under
the mortar. Over the years it softened the clay in the raw
(unfired)  bricks.  Watertight sealants will gradually soften
the clay under them.  It may not show in a year but it will over
time. <br>
 This church was in a quite dry climate near Santa Fe, New
Mexico.  If you would like more details I will look up the recent
Smithsonian article and put the page and issue on this net.<br>
 <br>
IT IS DANGEROUS TO TRY TO SEAL AN ADOBE OR COB WALL.  THEY NEED TO
BREATHE.<br>
<br>
Potassium silicate, I believe is a sealants that can cause this gradual
deterioration of unfired clay walls.    You may be
undermining your building.  Just what potassium silicate would do to
garden walls is another question.  Perhaps they would make the wall
last longer than an unprotected  rain drenched wall.  Much
better are the ideas of putting a roof on the wall with an <b>overhang
</b>and putting stones in it that stick out.  Even terracotta
(cooked earth) tiles that are not glazed, just low fired, would be good
protection even though they are a little porous.  Most of the rain
would run off.  If the wall breathed the little moisture that went
through into the wall would likely work its way to the sides and
evaporate.<br>
<br>
What is important to remember is that even inanimate things are dynamic,
changing slowly or fast depending on the climate.  In the Egyptian
desert they can last for thousands of years but there are few
places  that dry in the world.  Even the ancient hieroglyphics
thousands of years old, when inclosed and viewed by too many 
tourists can be destroyed by the moisture evaporating from their
bodies.  So we have to bend with the weather and the impacts of
changing climates and recognize that every move we make impacts the world
of future generations.  Acid rain, thanks to our  blind use of
technology, is decaying even stone monuments that lasted thousands of
years.  The automobiles in Athens are destroying the ancient
Athenian buildings, for example.<br>
<br>
Americans look for quick fixes.  When they are efforts to short cut
natural processes they always backfire.  Cob is great because it is
mostly a product of nature and when properly used and cared for can last
for ages.  Tune into it and it will give you a singing house. 
Try to defeat the natural process and they will let you down, or let the
roof down on your heads.<br>
<br>
Bob <br>
<br>
<br>
</html>

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