Cob in really cold climates

[Eric D. Hart]

Hello:
        Thought I would start off asking my first (and most important)
question about earthen construction, how does it do for insulation?  The Cob
Cottage Companies web page says in the "What is Cob" section "Cob's
resistance to rain and cold makes it ideally suited to cold climates like
the Pacific Northwest, ...."  Sorry, I've live in the Pacific Northwest and
it *does not* have a cold climate.  Cool and damp for sure but not cold.
Minnesota has a cold climate.  So my question is, what is the R-value of
cob?  Does anybody know? When it gets down to -30 F every year for a week or
so, you care about the R-value of a building system.   I have heard that
rammed earth does not work in cold climates because earth is great for
thermal mass but poor for insulation.  I don't see why cob is much
different.  In the little I read it seems like it works best in cool,
maritime climates (like England and the Pacific Northwest).  Just want to
get all the issues out on the table so we don't think that one building
system is the solution for all climates.  It seems to me that each climate
requires a different type of building system that utilizes local resources.  



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