Cob: Thin walls

[Shannon C. Dealy]

On Mon, 8 May 2000, Mafalda Stock wrote:

[snip]
> Recently thin walls have been discussed, including African methods of
> mud-building.  Which brings me to the mud huts that I saw in Iraq many
> years ago.  Somewhere I read that cob is suited to rainy areas such as the
> U.K. and the Pacific Northwest.  Does this notion take into account floods
> as well, or not?  Because I do remember that when the River Tigris
> overflowed, the dried mud huts would revert to the mud from which they were
> made, and many lives were periodically lost. Is it a question of variables
> in the mud-mixture composition or that cob wouldn't stand long soaking?
[snip]

While you can build with cob in a wet climate, it is recommended that you
NEVER build near/in a flood plain.  A really good cob mix should hold up
better to flooding than many traditional "mud hut" type techniques,
because it's high sand content will make it more resistant to water
absorbtion and slow the softening process, and the high fiber content
(compared to other earthen building techniques) will give it greater
tensile strength, but serious flood waters will sweep any building off its
foundation (cob or otherwise), and prolonged contact with standing flood
waters will still collapse a cob building, though it might last for hours
where a "mud hut" might collapse in minutes.

Shannon C. Dealy      |               DeaTech Research Inc.
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