Cob and Earthships

[Renewables at aol.com]

I was a total cyber stupe and deleted the private message the gentleman sent
to me privately, so I thought that I would combine the reply with the one
here.

In a message dated 2/25/99 8:48:49 AM Central Standard Time, kimrb at jps.net
writes:

> Reply-to:	kimrb at jps.net (kimelia)
>  The aforementioned lack of microorganisms is a problem in spades if you try
>  to make an organic system native to outdoors work interiorly. How will you
>  supply enough sunlight, how will you re-create the variation in
temperature,
>  the air circulation, the connection to other natural systems that are cut
>  off when you bring this system indoors. You run the risk of creating (very
>  quickly) a pathogenic bacterial environment. Basically you cannot create
>  outdoor diversity in an indoor environment. I would recommend people not do
>  this.

The front of an Earthship is called the front face and it faces south in the
northern hemisphere.  Inside the front face (all south facing glass) is called
the environmental interface.

The gray water systems that are used in Earthships function as a variation of
a wet lands gray water treatment system.  The gray water planter is sized in
relation to several factors including number of people in the dwelling and the
number of fixtures in the house.  There are two (well now actually three, but
I'll only cover two here) kinds of Earthships; Those with sloped south facing
windows (usually sloped 60 degrees to the vertical) and those with vertical
windows.  Vertical window planters do not protrude too far into the "Nest"
style Earthship so as to stimulate the plants growing in them.  They tend to
be the full east-west length of the dwelling. The sloped window version has
gray water planters much more organically shaped, with some resembling an
oblong crescent shape.  They also receive sun most of the year.  Window shades
are drawn down half way in summer to let the sun only directly bath the
planters.  Front dormer windows are opened up to let in fresh air above the
planters which sets of a venting path to the rear sky light.  The bleeds
excess humidity away from the planter area to the outside.

All of the fixtures in the home drain to a height above the planters.  The
gray water enters a grease/particle trap and then goes down into the planter.
The planter is multilayered.  Sometimes pumice lines the bottom layer, but
some have also used shredded and crushed plastic milk cartons which hold
special bacteria once the gray water planter is functioning.  The planter has
succeeding layers going above which go something like large rocks, medium
rocks, small rocks, gravel, filtration matt, sand, soil, compost, etc., (sorry
I don't have the guide in front of me).  The planter is also baffled to make
the gray water travel through as much surface area as possible.  As the water
continues to travel slightly downhill (1/4 inch per ft), it finally goes
through a peat moss filter and then into a tiny (50 gallon?) well lined with
big rocks.  There is some plumbing associated with the well, especially a PVC
water level viewing tube and some overflow tubes.  A big variety of plants
grow here, including flowers, vegetable plants, and fruit and nut trees.  I
have seen banana trees produce at 7,000 feet in NM in the winter.  Try eating
60 ripe bananas within 36 hours!  Tomatoes are more forgiving if you can keep
the white flies at bay.  To entice the plants to grow deep roots at first, you
must trick them.  You have to let the water raise in the gray water planter to
near the surface.  When the plants indicate they are doing well, you can
slowly lower the level of water until their roots are down into the 2 - 4 foot
level (much easier for trees obviously).  There is a 12 v DC pump in the
filtered gray water well.  Until the bacteria get well established, the gray
water will have a very slight sulfur smell although it is clear.  The filtered
gray water can be used to water the plants in the planter (especially the
spring garden plants you are starting or other inherently shallow rooted
plants).  The 12 volt pump not only pressurizes the line going to the faucet
(specially marked of course!), but it also goes to the toilet where no fresh
water is used.  The earthship collects rain water, filters it for human use,
produces gray water which feeds the plants in the planters and is partially
cleaned itself, and then is used in the flush toilet before going out to the
solar septic where the contents use sort of a solar collector to heat the
black water to above 160 deg F, and then out to the lined leach field.  At the
end of this leach field is usually another PVC access port where the processed
waste water is by now clear and odor free.  The lined leach field does not
allow this water to leach into the ground, but rather to grow rich vegetation.
It is amazing to watch the outdoor planters a blaze in multicolors while the
rest of the desert looks brown and drab.  The number of humming birds visiting
the planters is amazing at times.  The NM CID tested the output of lined field
and found no harmful bacteria, but lots of plant nutrients and some ash.

The above is not earthship technology per say, but has been adopted as
something desirable to do.  The average earthship uses 15,000 gallons of water
per year, which is equivalent to 60,000 - 100,000 gallons in a typical
American home.  Thanks to the technology, many NM homes could extend the
amount of time before the ground water really does run out.  Unfortunately,
this technology is real labor intensive and expensive to build.  Anything that
raises the cost of a tract built house is not well received by the public
unfortunately.

What does all this have to do with cob?  You thought I'd never get to that did
you?

This part is in answer to the gentlemen wanting to use cob as a replacement
for pounding tires and laying cement and aluminum cans.

Well, there are many, many folks that have learned the hard way that an
Earthship with a square footage of 2,000 SQ. ft will cost them $300,000+ if
they hire out all of the labor.  The tire pounding, the front sloping face
work, the adobe plastering, the large amount of cement work, the flagstone
floors, and the earthen floors all are very labor intensive and cost allot to
hire out.  Even if you do most of the work yourself it still costs allot
because of the technology factor.

Many folks who were former earthship enthusiasts are now checking out the
straw bale and cob lists saying that maybe I can still have my dream
sustainable natural built house at an affordable price if I learn their stuff.
Unfortunately we are all tainted because although we want to use much less
cement and more natural materials, we also want to bring along those gray
water planters and catch water cisterns to have our cake and eat it too.  The
biggest problem we have is that we want to try and make our new cob/straw bale
projects to fit a 2,000 SQ. ft building.  Anyone can tell you that a 2,000 SQ.
ft cob building is allot of work and kind of resembles all of the work that
constructing an earthship takes.

The earthship is designed to have buried east, west, and north walls.  In cold
areas, the bermed walls are insulated a couple feet below the berm's surface.
Cob walls cannot be buried.  Cob walls are designed to breathe.  It likes
periodic sun (especially in winter) to keep the walls warm and dry.  Cob,
exposed to continuous moisture, will deteriorate very rapidly and can cause a
catastrophic collapse of the wall.  An earth bermed wall would need some type
of vapor barrier in wet areas and would be subject to things I would want my
cob wall exposed too. The same way goes if you construct a gray water planter
using cob.  You would have to have some type of water proof liner and put up
with the consequences when in eventually breaches.  Also, the possibility of
dew point or humidity between the liner from the cold gray water and the cob
planter will probably give you problems.  It is probably best to choose
another material for this use.  Cement and cans works best for the earthship
planters, but I have resolved to not using either one of them and have decided
to use only natural materials.  As of yet, I don't know what those ideal
materials are.  My future house to be as I can envision it right now has no
internal gray water planter or greenhouse.  That might change, but for now I
will plan for a small 450+ SQ. ft round house with living roof and external
attached greenhouse for flowers and starting plants (as well as a larger
growing dome for other greenhouse stuff).  I am still learning myself.  We are
waiting until our son graduates from high school in a few years before we
built and to avoid a sickly long commute from where we want to build.

A cob novice,

Dave & Sheila Knapp ... who may be living in SW WI sooner than we think due to
the company I work for (while paying off our debts and saving up a grubstake)
being the victim of a hostile take over!
Winnebago, Illinois
http://www.bigfoot.com/~renewables/