Cob: Re: Cob & Steel

[ANovelli at aol.com]

Hi folks,

If a balehead might chime in on this interesting conversation...

One point I have not seen discussed is a corollary of the thermal 
transmission of steel. It is well known in bale circles that rebar pins 
"sweat", and over time create cores of rot around them, potentially weakening 
the steel and of course, destroying any resistance they offer to movement. 
While you are using a much lower percentage of straw in a cob mix, the clay 
may not help solve this problem. To my mind, I would keep the posts inside 
the wall footprint, where the steel and the bond to it is not a concern. 
Since the wall would not be load bearing anyway, all it would need is some 
kind of connection at the top to close the air space off and provide some 
stability for the wall. Sandblasting or etching and oiling the steel (if it 
is regular I-beam) is a nice way to keep a gun-metal finish I'ev seen in 
upper end homes.

I'm a little outside my area of expertise (drinking beer, watching the UA 
Wildcats), so be gentle in your corrections please :)

Tony

Tony Novelli
Assistant Director
Development Center for Appropriate Technology
P.O. Box 27513
Tucson, Arizona 85726-7513 USA
(520) 624-6628
(520) 798-3701 Fax
<A HREF="http://www.dcat.net">http://www.dcat.net</A>

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