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Cob
Building Tutorial
Chapter
2: Is a Cob Home a Good Fit for You?
The
fact that you bought this book tells me that you’re a bit
unconventional …or at least curious. You’re probably concerned about
the environment and a bit of a rebel. But before you dive into the
wonderful world of cob building, you should first decide if a cob home
is right for you.
 Although
cob homes can theoretically be of any size, cob lends itself well to
smaller homes. The size of your finished home is directly proportional
to the amount of time and patience you have to put into it. Cob fits in
well with a ‘less is more’ philosophy of life, and these homes can
be built small yet comfortable. Smaller homes use up fewer resources, so
if you’re planning a cob home it’s probably better to go with a
smaller size.
Although
cob is a very durable material, it does require some routine
maintenance. About once a year it’s a good idea to check for cracks in
the plaster finish, both inside and out, and repair any small gaps
before they become larger. Although cob is a very forgiving building
material, a well-built cob home requires less maintenance than a shoddy
one. The more consideration you give to proper construction and water
runoff, the less maintenance you’ll have to do. If you’re unsure of
your skills, you might want to start off with a smaller structure first.
Maybe a cob storage shed, playhouse, or even a cob oven or sculpture. If
properly built, most of the maintenance involves minor repairs to the
plaster finish. These repairs can usually be accomplished in an
afternoon.
Some
people have reported problems with silverfish and other insects. These
problems are rare and are usually the result of easily repaired gaps in
the plaster finish or flooring. They are more common with earthen floors
than with floors finished in tile or brick, but they do occasionally
occur. Although I’ve had no experience with this technique myself,
I’ve heard that mixing a little red pepper in with the cob will keep
most insects at bay without having to resort to toxic pesticides.
 A
major consideration for your cob home is the location. Unless you live
in an intentional community, most subdivisions will frown upon something
as unconventional as a cob home. Not that there aren’t subdivisions
that may accept such structures, but they are the exception rather than
the rule. To me, cob is best suited for country living. A well-sculpted
cob home fits in beautifully with a natural landscape. If you already
have a site picked out, you may want to talk to your neighbors to find
out what they think. You may be pleasantly surprised to find that they
express an interest in your plans.
By
far the greatest hurdle to overcome is getting the local building
inspector to issue a permit for your home. Although cob is not forbidden
by most building codes, many inspectors have little or no experience
with the material. Current building codes protect the manufacturers and
the contractors more than they protect the consumer. If you build and
something goes wrong, the building inspector is liable; therefore they
are hesitant to go out on a limb to sign off on something with which
they are unfamiliar. In the past I’ve found that the best way to work
with a building inspector is to ask a lot of questions. If they feel
they are being kept in the loop, many building inspectors will be more
willing to work with you. An adversarial attitude will gain you nothing
but an adversary, so try to be as friendly as possible no matter how
frustrating the process becomes.
 I’ve
seen some cob sites on the Internet that suggest skipping the building
permit and just building on your own. I wouldn’t recommend that route.
Although penalties vary from state to state, they can sometimes be quite
severe, including forced tearing down of the structure you worked so
hard to build, and in some cases even jail time! Building inspectors,
like most state and county officials, are overworked. You may think
you’ve gotten away with something for a year or two, then suddenly one
day they’ll be knocking at your door. This is especially true if you
have neighbors who object to your home. It only takes a phone call to
the local office. In one case I heard of, a family lived happily for
almost seven years in their cob home. They had built without a permit
and thought they were home free for all those years, then one day the
building inspector showed up. They were heavily fined and forced to tear
down the structure. They eventually rebuilt a permitted home that was
virtually identical to the one they had to destroy. A lot of time and
effort could have been saved if they’d just gotten the permit in the
first place.
 Since
there is no building code strictly for cob, most building inspectors
will try to shoehorn cob into another category. Some codes cover adobe
construction, and cobbers have had some success in convincing building
inspectors that cob is just a modified, sturdier form of adobe. It is
also sometimes considered a form of masonry, but that’s stretching
things a bit. It really depends on how much latitude your building
inspector is willing to grant you. It has been my experience that if you
have a firm roof support, the building inspector will grant you a lot of
leeway in what the walls are made of. Although cob is load-bearing when
built properly, most building inspectors unfamiliar with the material
won’t grant a permit without a series of tests if the walls are going
to be load-bearing. When I’m working with a building inspector who’s
a ‘cob virgin,’ I generally build a gazebo-like structure first, in
which the roof is supported by poles or pillars of some sort, then fill
in the walls so that they are not load-bearing.
Getting
a permit is probably by far the most time-consuming and costly part of
building a cob home, especially if your local building inspector has
little or no experience with the technique. If you have the misfortune
of running across a particularly stubborn inspector, you might consider
trading a bit of frustration for the expense of hiring an architect
familiar with cob. That in itself can be a chore, as such architects are
often hard to find. A good place to start would be your state’s
Architects’ Association. You might also check with your local colleges
and universities, especially if they have a school of architecture or
engineering. There are also several great places to look on the
Internet. A couple of my favorites are the Green Building Network at
www.greenbuilding.com and Green Home Building at
www.greenhomebuilding.com.
If
you haven’t already selected and purchased a building site, you might
want to check with the building inspector’s office in the area
you’re planning to buy. If you can afford the luxury of choosing your
location in a wide variety of areas, you might want to purchase land in
a county where the building inspector is open to what you want to do. If
you decide not to buy in a particular county because of a difficult
building inspector, be sure you let the inspector’s office know, in as
friendly a way as possible, that you chose not to purchase land in their
county because the inspector’s office had no experience with cob. You
might also let the local Chamber of Commerce know why you rejected their
county. Once they know why people are avoiding their region, they might
be more amenable to changing things for the next cob pioneer who comes
along.
 If
you haven’t purchased a site yet, you’ll want to read the chapter on
site selection before making a final decision. There are many general
guidelines that will help you determine the best place for your new
home. If you’ve already purchased a site, don’t worry. There are
still steps you can take to make sure your cob home is a perfect fit.
What’s
it like to live in a cob home? Is a cob home right for you? Although cob
homes are usually smaller than the average house, many who have chosen
this type of dwelling find that once they’ve moved in, the smaller
size is actually more comfortable. Since cob homes lend themselves to
more organic shapes, space is used more efficiently. Vertical space can
be used for storage, eliminating the need for additional floor space for
storage. The smaller size means less area to clean. It also means less
area to heat and cool.
Ideally,
a cob home is an integral part of a more sustainable lifestyle. A
smaller home equipped with energy-saving appliances and planned with
passive solar design in mind means less energy demand. If you are
incorporating an off-the-grid form of energy such as solar or wind
power, your energy demands will be much smaller with a well-designed cob
home. Less energy requirements mean a less expensive power source. By
incorporating a rainwater catch system you can also reduce your need for
water from public utilities. If you have a well instead, your well
won’t be taxed as much (if you live in an area with a fair amount of
rainfall) by installing a cistern. If you really want to maximize your
sustainability you can even plant a vegetable garden right outside your
door to supplement your grocery shopping.
If
you suffer from allergies or asthma, you may find that your symptoms
improve or even go away entirely once you move into your cob home.
Unlike commercially manufactured housing, cob homes ‘breathe.’ The
natural materials used in their construction contain no toxins that seep
into the home’s atmosphere. The air can circulate freely through the
walls without producing drafts, allowing fresher air without
compromising heating and cooling. The walls also contain a great deal of
thermal mass that regulates the temperature by storing heat and
radiating it during the colder periods.
 Some
people think that because cob homes are made of clay, sand and straw,
that they are dirty inside. This isn’t true! Once the cob walls are
finished, they’re covered with plaster, in the same way that walls in
a stick-built house are. The clay is contained behind the plaster.
Another
thing to think about when deciding whether a cob home is right for you,
is the labor involved. Cob doesn’t rely very heavily on machinery.
It’s truly hands-on in that the cob is mixed by hand (well, by foot,
actually). Cob walls are one to two feet thick, and about six to eight
feet in height on average. The clay, sand and straw are mixed together
by something called the ‘cob dance,’ in which you take off your
shoes, mix the ingredients together, add water, and stomp until it’s
the right consistency! Once the cob mass is ready, it’s shaped into
balls (the ‘cobs’) that are about six inches in diameter. Consider
that you’re building a one or two-foot-thick wall at least six feet
high, using balls of cob a little bigger than a grapefruit, and you can
see that patience is a considerable factor. It could take up to a year
or longer to build your cob home, depending on how many hands you have
available to help you. So if you’re in a hurry for a house, cob may
not be for you.
 Cob
does require some physical activity too. Mixing the cob requires you to
stand in one place and trod the materials for a large part of the day.
Carrying the materials to mix the cob is also a physical activity, as is
building the walls themselves. You don’t have to be in excellent
physical condition, but it pays to be at least somewhat in shape. I
recently read a story about a 72-year-old grandma who built a cob home
herself in a little over a year, so you don’t have to be an Olympic
athlete to build with cob. In fact, if you’re not in shape, cob is a
great way to exercise while building!
One
word of caution on the labor involved: A cob home is usually built with
a stone foundation, about eighteen inches above the ground level. These
stones are usually found on-site and carried to the building location. A
20-foot circular home would require about eight tons of stone for the
foundation. This is by far the hardest part of the process, though, so
once the stone foundation is laid, the rest is fairly simple and not as
physically demanding.
Now
that we’ve discussed the disadvantages of cob building, let’s look
at the benefits. If you haven’t been scared away from this versatile
building style yet, read on…
The
modern building industry is geared towards protecting the building
contractor, not the homeowner. You’ll discover this once you set out
on the road to procuring a building permit. Unfortunately, these
self-appointed ‘experts’ have convinced the public that building
your own home is too difficult, time-consuming and specialized to be a
reasonable ambition for most of us. Nothing could be further from the
truth! Cob building is so easy a child can do it. When I was a young lad
growing up in the backwoods of South Carolina, I ‘invented’ cob
building on my own by building forts of clay, sand and straw down by the
creek. Back then, I didn’t know what it was called. It just came
naturally to me. If a ten-year-old child can figure out how to build
with cob, so can you!
Consider
the fact that at least one-third of the world’s population is
currently homeless or living in substandard housing. Could you imagine
what would happen if all of these people learned that they could build
their own homes literally from the ground up?
 The
current building codes very rarely incorporate building with earth. They
limit options to commercially available methods of construction. This
means increased costs and increased damage to the environment. We wind
up paying architects, engineers and builders a lot of extra money for
our homes, when we could build them ourselves! Consider the fact that
when you buy a home, you usually sign away 30 years of your
life to a mortgage, just to pay for these added expenses. While
cob building is labor intensive, taking up to a year to build a single
home, a cob home is generally paid for as soon as the last nail is
driven because it is made from natural materials obtained directly from
the building site. Isn’t it worth a year of manual labor to be free of
30 years of mortgage payments?
Not
only are cob homes less costly due to using natural building materials,
but they are less expensive where utilities are concerned as well. Cob
walls contain a lot of thermal mass. If a cob home is designed using
passive solar techniques (see ‘Passive Solar Considerations’),
heating and cooling costs can be greatly reduced, minimizing utility
costs. Well-placed windows also offer maximum use of natural lighting,
minimizing the need for artificial lighting sources. Cob walls are
fireproof, and they naturally lend themselves to alcoves containing
votive candles or lanterns.
Cob
homes work well with alternative forms of energy such as wind turbines
and solar panels. Since you sculpt the home yourself, you can
incorporate these devices into the home quite easily, making them a part
of the home design.
 A
smaller home built with natural materials is something the whole family
can get involved in. While conventional construction is noisy and uses
dangerous equipment, cob building is done mostly by hand and uses
hand-operated tools. Since it is a safer alternative, it is more
enjoyable for the whole family. Even small children can get involved! If
they know how to make a mud pie, they know how to cob! Once the home is
completed, your children can take pride and satisfaction in the fact
that they made a positive contribution to building your home.
Since
cob uses natural materials, it has less negative impact on the
environment. Materials don’t have to be transported over long
distances, using fossil fuels that contribute to air pollution and
global warming. The materials are non-toxic, so there is nothing in a
cob home to poison the atmosphere or contaminate the ground water. Cob
can be used in a wide variety of environments and climates, from the
humid British Isles to the arid deserts of the American Southwest. In my
opinion, it is the most versatile form of building on the planet!
About the pictures in this
tutorial: Not all of the cob structures in the pictures shown here
were built by the Culture Artist Cobbers. Many are from cobbers at various
sites around the world. I have attempted to get permission for all the
photos used on this site, and to properly credit them wherever possible.
When the cobbers in question have a website, I have tried to link the
picture back to their site, or list them in the Cob
Builders' Directory, or both. I have made every effort to gain
permission for all the pictures shown. If I inadvertently used one without
permission, please contact me at chuck@cultureartist.org
and I will either credit the source or remove it. Thanks!
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