[Cob] Cob on a north slope CA mass inefficiency

[Barbara Roemer]

Janet, Charmaine suggested I pop in here.  I've followed your posts loosely,
but don't know your zone.  Ours, on the federal schedule, not Sunset Mag, is
about 7.5.  We have southwest-facing land, heavily timbered.  The timber
breaks cold winds, the slope drains off cold air, our coldest lows lie at
about 18 degrees, with normal winter low temps anywhere from 22-38 degrees.
We have hot summers, though over 90 is very hot for us, with a 30 degree
diurnal difference, so it still cools off at night.  The heavy yellow
pine/mixed woodland forest here transpires plenty so the air isn't as dry as
it would be otherwise.  Our elevation is about 3500 feet, up on the San Juan
Ridge above Grass Valley/Nevada City in the northern CA Sierra foothills,
39.3 degrees north, 121 degrees west.

With all that as background, I wouldn't build a cob house here.  I have
friends with one, and their rocket stove is mostly fired all winter.  we
helped other friends nearby with their straw clay LaPorte designed home.  It
stays toasty, but has a LOT of  straw, an insulated foundation, and a
heavily insulated roof, as well as a sunspace bump-out on the southern side
& careful southern siting.  They also put in a Tuli Kivi baffled masonry
stove, a major investment, but works beautifully.  You can see all of this
at LaPorte's website.

A hybrid is the way to go for this climate.  I'd put bales on the north and
west, heavy thermal mass in the floors and interior south facing walls,
strawclay on the south because it's easy to deal with odd spaces around all
those windows,and probably straw clay on the east - mass for summer and
insulation for winter.  Even if it's a small house, you'd want a structure
in conditions similar to ours to be super efficient, and a hybrid best
addresses the varying conditions. Relative tightness of your building
envelope also matters - a LOT.  Good luck!

Barbara Roemer