[Cob] On Top of Tires also outgassing.

[Amanda Peck]

That could work.  Or even "stabilized soil cement" (generally about 5%) 
concrete filling in the arcs on both sides of the point.  I have an internet 
acquaintance who does all of his cob with stabilized soil.  Don't know if it 
means he doesn't need as much clay.

I have mostly been fussing about cob on top of tires.

Earthbags are mostly those poly bags, can be bought on a roll in various 
sizes.  and get covered with something after the walls are up.  Just like 
the tires.

Consider earthbags.  This is a good book.  More information using this link, 
but

www.dirtcheapbuilders.com

belongs to this forum, and she does give better service.

http://www.amazon.com/exec/obidos/tg/detail/-/0865715076/102-5033885-9976111?v=glance

I don't know about tire outgassing.  New tires certainly have a distinct 
smell.  Used in a house they are always covered, if with something 
breatheable.  The Farbers (the tire fun "re tired" guys out of Utah) say 
they have not heard anything bad about using used tires for raised garden 
beds, and invite an exchange of information.

http://www.tirecrafting.com/04FAQ/04faq.htm

I seem to remember some old organic farm in Missouri or somewhere thinking 
that used tire treads made great raised beds, cut through the tread, 
straightened and set with stakes.
.................
Beno wrote:

Okay, so it sounds like a test of the tire foundation is in order. But what 
of setting cob on top of the tires? After all, they meet in a point. Won't 
that point be unstable and suseptible to cracking? Should I build the 
foundation one tire higher and then downfill cob to the next lowest level, 
or will that lowest portion of cob not be structurally significant? Or, 
perhaps I should search around for some larger size rocks to stack on top of 
the gaps between the two highest layers of tires?