[Cob] Cob Cistern

[Barbara Roemer]

Janet, this is mainly for you, but perhaps others will jump in.  The only
cob water holding structures with which I"m familiar are like Minke's sinks
and tubs, meant to hold water for a short period.  My earthen floor resists
water to the point that water beads up on it, but only for a few months
right after it's been oiled.  After 5 months or so, liquid will sit on it,
but will eventually seep in a bit.  (I know this first hand after cleaning
up after a sick, peeing dawg two days ago.)

I can't imagine holding any amount of water for a length of time relying on
only the surface sealing to contain it.  Defies hydrology!  The homemade
cisterns I've seen are  ferrocement with lots of wire and ties, and they
work very well if well-done to begin with.  All that said, I'd love to hear
your plans for a cob structure.

Barbara in the Sierra Nevada foothills