Cob: Oklahoma thoughts and concerns

[Darel Henman]

Shawn,

my response is below.


swboltin at excite.com wrote: 
>........ snip.......
> 
> I was curious, I live in Houston and 80+ is common at night.   Accompanied 
> of course with our high humidity.  Is this an issue with the stability of
> cob or just factor in with the comfort level?


Shawn, it was 93 deg F high and 80 deg F low yesterday and this
morning.  It gets just as humid here in Japan I think as Houston,
because of the tropical waters and winds, coming up the Pacific.  Japan
has used a method of wattle and duab, though, the application is in
layers from in to out, rather than from bottom to top like cob, and with
each successive layer a finer and finer finishe layer is applied, unless
a rougher look or a look with straw pieces flying in swirls like in
tornado look is desired.  

This method of building has been in use since about the year 710
C.E.(note: C.E. = Common Era, so about 1300 years ago), in the building
of "Horyuji" and it is still being used, though now it is expensive and
is considered high class, becuase it takes longer to build and they use
experts for building and finish work.  This is not a new and untrusted
building technology.

It is used in the U.k. as well for hundreds of years and they have a
very damp climate as well.

"Horyuji" temple was designated one of the world's most important
cultural heritages in 1993.   The grounds' walls around the temple are
all rammed earth with lime, the walls of the temple are all cob/daub
type material applied to a bamboo and/or tree branch wattle, with the
white walls being a hard kao (kaolin?)  clay soil finish. All building
walls within wooden tempbers are cob/daub with finely screened earth
made plaster finish.

Here are some pictures that somebody took and made available on the web. 
 Look at the earhen walls between the tembers.

http://202.23.150.181/users/kkitao/pictures/ikaruga/horyuji/

New houses in the country side still are being built with earthen
walls.  I got a picture of one, unfortunately the underlying wattle was
already covered.  I only got the hard clay 1st coating.

So I don't think you Houston temperatures and humidy would present any
problem to an cob bulding and in fact it should perform well and be less
humid inside then stick or concrete buildings, due to soils breathing in
of and ajusting interior humitidy swings as well as temperature swings.

> This would be something
> that I would definitely like to know prior to jumping in.   Also, the
> developement I am in, my house included, is developing problems in
> relation to driveways and in some instances foundations, all of the slab.
> It seems that the soil wasn't compacted enough and cracks are developing.
> There are a couple of driveways that have a large portion of the soil
> underneath has washed out and are being supported by re-bar alone.   I
> have read some of the other emails stating that with cob, soil compaction
> is not an issue, and in fact is often avoided.  How does a wall that is
> all one piece get around this?   Any help any of ya'll can shed on either
> issue is greatly appreciated.
> 
> Thanks, Shawn