[Cob] Straw's Out. How About Palm Leaves?

[Shannon C. Dealy]

On Thu, 22 Sep 2005, Patrick Newberry wrote:

> If one doesn't have straw and ends up building with earth only, I
> believe that the shape of the building can help as well. E.G a rounded
> structure would stand a better chance than a square structure. Thus most
> of hut type mud building I saw where round.

Circular will help, but the fiber is far more critical if earthquake is a 
consideration.  Cob structures that have been through seismic tests or
real earthquakes, after they fracture will often continue to be held 
together by the fibers, this helps to protect the occupants (and 
undoubtedly reduced the amount of structural damage).  Of course in an 
area where earthquakes are rare (and I think this is true for much 
of Africa) and/or very mild, the local building traditions may not take 
them into account.  I don't know anything about the buildings you are 
refering to, but alot of the circular huts in Africa are wattle and daub, 
which is basically woven twigs with a mud plaster and the twigs 
would provide alot of tensile strength (there are of course all sorts of 
variations on wattle and daub).

FWIW.

Shannon C. Dealy      |               DeaTech Research Inc.
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