Cob RE: light clay in bags

[Kat Morrow]

Dear Pat,

I was on-line at my friend Kat's, saw your post and had to respond.  I
worked with Nader Khalili for several years, and we did just what you are
suggesting.  We used earth bags until they started to collapse inward (we
were attempting a hemispherical dome)  We turned to light-clay bags (this
was back in '92 before we had even heard of the technique) because we had
no other recourse.

The one problem with the light-clay bags is that they are kinda squirrelly.
We ended up having to put up a sacrificial form which we made of PVC (real
minimal- six spokes to a central hub) this helped keep the bags in place
until we could plaster. We used a lot of plaster, and thats really what
became the structure of the roof.

If you made a catenary roof, using a corbelling technique, you might be
able to get away with not using the form.

Good luck!

Joe Kennedy

>You could put the light clay in bags (as in Nader's technique) and
>the bags would be the forms.
>
>I'm going to be attempt this sometime this year for the upper
>sections of a dome. I'll use earth for the lower portions of the dome
>and the light clay for the upper sections ("roof") of the dome.
>reduced wieght, more insulation, easier to haul up etc...
>
>Pat