Cob sledgehammers and heat retention

[David DeFauw]

Dear April,
	I have just researched the available data about cob and energy efficiency
in cold and cloudy climates.  Some of my questions and doubts I also put
out on the listserve and received some very charming responses, especially
some anecdotes from Devon area cob dwellers.  I searched many other sources
and had e-mail discussions with earth building experts.  I also took the
cob building workshop in Cottage Grove, Oregon.
	Living in Portland, Oregon, I focused on this drippy, 40ish degree winter
climate with little temperature variation, where its so cloudy that some
days I wonder if the sun ever came up.
	After looking at the data here are my opinions and conclusions:
	The benefits of thermal mass are less important in areas with low daily
temperature fluctuation and little sunlight.  In sunny desert climates,
thermal mass evens out the extreme daily temperatures, leaving the inside
temperature relatively constant.  The sun heats the walls, which act like
solar collectors, especially if the walls are dark, adding to the energy
savings and comfort.  In climates that do not heat up during the day, and
have little sunlight, an R-6 cob wall may not be the right choice.  
	Still, walls are only part of a house.  Ceiling insulation (put in lots of
it), windows, and solar orientation (lots of south windows, some east, a
few west, very minimal north) are equally or more important.
	One of cob's great benefits is its low embodied energy.  The amount of
energy it takes to manufacture and build a modern house is astounding. 
>From the earth's standpoint, it makes little difference if a house takes
little energy to heat if it took decades worth of heat to build.
	A more energy efficient option for a severe cloudy climate might be a wood
stingy post a beam frame, straw bale walls, a poured adobe floor, interior
cob pony walls and benches, and passive solar design.  This is a proven
winner that is permitable anywhere.  It gives the benefits of thermal mass
and those of super insulation.  It also would work well in earth quake
country (where are you located anyway).
	That's some of my 25 page paper condensed to a few paragraphs.
	Good resources are the University of Plymouth, and the University of New
Mexico, where Professor McHenry resides (he is the author of a good book on
adobe and rammed earth construction).  Also a good over all source of
commercially available, more earth friendly building products is the "Guide
to Resource Efficient Building Elements, 6th edition," by Tracy Mumma.  It
is self published by the Center for Resourceful Building Technology,
Missoula, Montana.  Their e-mail is CRBT at montana.com. 
	Feel free to contact me at davidde at hevanet.com or on the listserve but I
will be gone to sunny Bali and India after December 14.
Goodluck,
David DeFauw.
----------
April Genth wrote:
>         As well, do you know if a cob home would be energy efficient in
> heating costs in a region where winters are cold with a mean temp. of 22
> degrees F in January- where it's not very sunny?
(snip)
>         I'm trying to prove, in a paper, that a cob home would save the
> owner money in heating costs in temperate cold, cloudy winter regions. 
If
> there are limitations like low r-values, then what are the low-cost
remedies
> I can offer?