Cob: questions

[Shannon C. Dealy]

On Wed, 25 Sep 2002, Angy Violet wrote:

[snip]
> I also need to know about the consistency of the cob
> mixture, as we would like to start experimenting with
> it, by making statues,etc.

There is some discussion of how to make cob in the archives, check the
oldest archives first:

   http://www.deatech.com/natural/coblist/

and of course there are a few books on cob which could help you as well.

> My next request, is for any information regarding the
> specific properties of cob building. Why can you only
> build it 16ft? How does it hold in the snow? What are
> the disadvantages?
[snip]

There is no 16 ft limit, but the higher you go, the thicker the wall must
be lower down in order to support the weight of all the cob above it.
This means alot of extra work for each additional level on your building,
so for most people, one or two levels is all that is practical.  Cob
doesn't mind cold, only water, so it's best to try and keep the cob away
from drifting snow, since when it melts it will probably tend to errode
the surface a bit, though it should take many years to do any significant
damage, and it can be easily repaired, so this is not much of an issue.
The only significant disadvantage that I see with cob is it's poor
insulation value, but careful design in moderate climates can pretty much
eliminate this issue, and in more extreme climates, wrapping the exterior
of the cob in insulation would be the best approach, a number of people
have started experimenting with wrapping cob in straw bales.

Shannon C. Dealy      |               DeaTech Research Inc.
dealy at deatech.com     |          - Custom Software Development -
                      |    Embedded Systems, Real-time, Device Drivers
Phone: (800) 467-5820 | Networking, Scientific & Engineering Applications
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