Cob: cob in the great white north?

[Joe Leonard]

Believe it or not we got a building permit for a Cob/strawbale sq. ft. home in
Idaho.  They approved an earth floor, cob interior walls, cob plaster, and a
rubble foundation. The health dept. also permitted a backwater wetland. We
decided to go post and beam to speed up the permitting process.  The post and
beam system including the roof  cost less than $3.00 sq.ft. the trusses are
going up this week.  The health dep. is requiring a 72' infiltrator to back up
the wetlands, I doubt that it will ever be used.  I am convinced that in the
north straw is the best material for outer walls and interior walls of cob for
its mass. We are building a covered porch on all four sides to protect the cob
stucco.
Joe Leonard

Fetter, Tom wrote:

> On the list from time to time, I've heard folks speaking about "cob in cold
> climates."  Cold's a relative term, it seems - and I suppose it reflects
> that most of the list members live far to the south of me!  But it seems to
> me that by itself, cob's enormous thermal mass would only compensate for its
> low R-value if the ambient temperature outside didn't stay frigid for long
> periods.  Surely a thermal fly-wheel, however large, must be insulated in
> really cold climates, even on the south side of the building.
>
> Sooo ..... what's the best option?  Here in Edmonton Alberta, December
> through February temperatures range from 10-40 below zero, with only a few
> days at either end of winter with balmy above-freezing temps.  Has anybody
> got beyond talking about cob/strawbale hybrids, and built one?  Would you
> maybe put the cob structural wall on the inside, strawbales outside, and a
> thin cob or mud plaster shell?  Would it be necessary to "pre-load" the
> bales to compress them to account for eventual settling of the bales in a
> hybrid as it is in more conventional strawbale construction, or would the
> cob holding up one side of the bale prevent that settling?  God knows, the
> cob won't settle!
>
> Finally, does anybody know how well cob and/or earth plasters hold up in
> rather severe freeze/thaw cycles?  Currently, when we face houses up here
> with brick, the bricks must be fired at a high temperature to prevent them
> taking up too much moisture close to freeze-up time.  Otherwise, the
> moisture could cause the brick to crack and flake.  I'm concerned that
> unfired mud could do the same, especially close to the ground where there
> could be splashback from late fall rains, or damp from melting snowdrifts on
> warm(ish) late winter days.  Having said all that, there are lots of lovely
> 80 year old brick houses 'round here, and the brick kilns probably weren't
> blazing hot - maybe I'm over-concerned about nothing?
>
> Tom Fetter.