Cob in Snow

[Speireag Alden]

Sgrìobh PEACE!:

>Can you use most any roofing material?

    Yes.

>Are cob barns feasible?

    Yes.

>Could a person use cob for all their outbuildings?  Such as a solar house,
>hay barn, well house, etc?

    Yes, but it may not be the best answer to all questions.

    I looked at cob when I was designing my house here in New Hampshire
(I'm currently building).  I decided that it was not climate-appropriate
for my area.  You're going to settle in an area which is potentially
harsher than mine.

    We have harsh winters up here, though we're not at all far above sea
level.  We get lots of snow most years, and I have seen overnight
temperatures below negative forty.  I have lived and camped in the high
Sierra, and I know that you will get lots more snow than we do here (though
drier), and probably experience lower temperatures, depending on where you
end up.

    Cob is a nifty material in many ways, but it is not a good insulator.
It is excellent thermal mass.  So, cob works well in climates where the
average temperature over a day or two is not consistently much colder than
comfortable.  Like adobe, cob's thermal mass acts to smooth out the daily
temperature curve; it absorbs excess heat gradually, and then gradually
gives it off when the air temperature drops below the temperature of the
cob.

    There's the rub.  If the air temperature *stays* low, then so will the
temperature of the cob.  Yes, you can make up some of that difference with
passive solar techniques and by heating with some form of fuel.  That's
what makes cob work in the winter as far north as Oregon and Washington.

    Beyond a certain point, however, you need more than thermal mass.  You
need insulation.  I have talked to people who have lived in stone houses in
Minnesota, and they tell me that they're great in the summer and really,
really cold in the winter.  Cob is better than stone for insulation, but
not by a lot.  For a continuously occupied building, you can do very well
by enclosing your thermal mass inside an insulated envelope.  Then the heat
transfer to the outside is slowed down, and the thermal mass acts even more
effectively to keep things comfortable, especially in combination with
passive solar techniques.

    There are plenty of ways to build in your climate, but I think that if
you rely only on cob you'll be disappointed, and cold.

    My personal choice, which may not be best for you, was to build a straw
bale house.  The roof is insulated with mineral wool, under the thermal
mass of a living roof.  The walls are straw bale, with earthen plaster on
both sides of the bales.  Plenty of thermal mass inside, in the floor, and
insulation under that.  Passive solar orientation and window siting.  Small
footprint for ease of building and heating.

    So I'd look at a super-insulated shell, with thermal mass inside.
Could be straw bale, could be something else.  Take a close look at going
underground, which would be very effective in your area.  Check out Rob
Roy's, _The Complete Book of Underground Houses_.  For straw bale, check
out _The Straw Bale House_, by Athena & Bill Steen and company.

    I'd also look seriously at a masonry stove, which is another
application of the thermal mass idea.  Instead of burning large wood below
1000 degrees, you burn small wood in occasional very hot fires.  The stone
in the stove absorbs the heat of the fire and gives it off moderately and
gradually over time.  There's no creosote build-up because the fire is so
hot that the gasses also burn, and you can burn a wider range of materials,
including stuff which we normally refer to as "slash".  There'll be no
shortage of that kind of thing in most Sierra locations.  Plenty of pine
branches.

    For buildings which don't need a particular temperature to be
maintained, cob should work fine in the high Sierra.  Storage sheds come to
mind.

    I hope that this helps.  Good luck.

-Speireag.
0>>>>>>(---------------------
Speireag Alden, aka Joshua Macdonald Alden
Joshua.M.Alden.91 at alum.dartmouth.org
Usually found somewhere in the wilds of New Hampshire.
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