Cob RE: light clay in bags

[Patrick Newberry]

Joe:
First of all thanks a million for responding!!!!
Hey being on the bleeding edge of alternative building technology can 
have it's ups and downs. 

I am   planning on a catenary roof. I am figuring that you can 
corbell a bit more with the straw coated clay than with the earth. 
Maybe three inches per row? since I'm 22 feet across on this dome so 
that would be 44 rows to get to the top. I plan on a sky light at the 
top so it  really would be lower based on the diameter of the sky 
light I put in. Now the one SMALL experiment I did with the clay 
coated straw in the bags was done in a arch and only a couple 
sections in an arch followed by some regular earth filled bags. The 
hieght of the straw bags seem much lower than the earth filled bags 
because of the weight on top and the fact that the straw/clay will 
compress tighter than the plan old earth.  Thus the hieght to 
corbell inward ratio would be such that it shouldn't be as high 
as a earthen corbelled dome. It's been about a year and the small 
expermient has  held up real nice but like I said they only made 
up a few layers about 2/3 's way up an arch. (a window arch in my 
superadobe out house!)
if you want to see a photo:
http://www.gnat.net/~goshawk/patnarch.htm

Now the 64 dollar question?
if you had a 22 foot dome would you use strawcoated clay in bags? if 
not then what?

Love and Light
Pat
Mauk, GA
http://www.gnat.net/~goshawk



> 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
> 
> 
> 
> 
    "I see nobody on the road," said Alice.
    "I only wish I had such eyes," the King 
    remarked in a fretful tone. "To be able to 
    see Nobody! And at that distance too! Why, 
    it's as much as I can do to see real people,
    by this light!" 
                     - Lewis Carroll,
                       Through the Looking-Glass