Hi Amy; Big Welcome to Permies!
I have added your post to the cob forum.
Your at the right place to learn all about cob building!
I have never used cob for a structure myself. Only while building
rocket mass heaters!
I suspect that in your location ... you won't need a rocket heater!
But if you do ,drop on by the
rocket mass heater forum. We will chat your ear off.
You've already met the forum leader !