[Cob] Buttresses

[Kim West]

Does anyone here know whether a rounded rectangle shaped building will 
require buttresses like square ones do? Our trench was relatively 
square, and so was the concrete beam and the stone stemwall [we used 
urbanite that was very near to right angles on the corners]. The first 
[approximately] 1 foot of cob was somewhat rounded, but from there on up 
we intend to make the somewhat rounded corners rise at a steep angle and 
end up a rounded rectangle. The buidling is 16'X16' interior with 2 foot 
thick walls where the cob meets the stemwall. The walls aren't exactly 
straight lines--they undulate since we decided to follow the natural 
curves of the stones in the stemwall. If square it should require one 
buttress per side. What if it ends up a rounded rectangle? Will it still 
need buttresses?

Thanks for all of the replies to my last post and for any help with this.

Happy cobbing!

Kim