[Cob] self-building - ovens vs. dwellings

[Ocean Liff-Anderson]

It is possible to build an oven with very little instruction,  
especially since Kiko Denzer has outlined in excruciating detail all  
the information necessary in his book, Build Your Own Earth Oven.

An oven is a simple dome structure, and once fired most of the straw  
"cokes" (burns to carbon without any flame) and no longer yields  
strength to the oven.  The domed-nature of the oven is supported in  
part by the lightly-fired clay center, which now resembles a weak  
porcelain.

Building a dwelling or other structure where people will be inside,  
under a wall-supported roof is another story altogether.  I would not  
recommend it.  The roofing and walls of a cob building can weight  
several thousand pounds, and while your oven's collapse may ruin  
dinner, a building's collapse will definitely ruin your day.

People have been killed when improperly built cob walls failed.

> I have never taken a workshop nor have I talked to anyone else who  
> built
> with cob in person and yet I have built an exceptional cob oven all
> because of the confidence instilled by the work of Kiko Denzer, Becky
> Bee, Lanto Evans, and many people on this very list. I have never  
> built
> any building from scratch before, food yes, structures no. Then again
> there haven't been any given in this area either :/
>
> Peter Kaulback
>
> Ocean Liff-Anderson wrote:
>> this question reveals much that needs to be learned...
>>
>> how can you be "ready to cob" if you don't know why straw is included
>> in the mix???  just where have you learned about cob, and from whom
>> did you learn it?
>>
>> in order to mix and build with cob, you need to know several things -
>> quality of clay, the right kind of sand, the best quality straw, and
>> the right mix of all three, along with water to mix them into cob.  i
>> can't believe that there isn't any straw in the state of georgia.
>> what do farmers do for their animal bedding?
>>
>> don't build with cob until you take a workshop, from someone skilled
>> in cob building, who can then explain all you need to know - the
>> proper way to make a good cob mix, a good foundation, a good roof.
>> if you are planning to build a structure which will be inhabited, you
>> must do so safely, or face the possibility of a catastrophic failure!
>>
>> sorry to be the harbinger of doom and gloom,
>> ocean
>>
>> On Jul 12, 2007, at 10:20 AM, Damon Howell wrote:
>>
>>> What is the purpose of straw in a cob mix? Nobody seems to "really
>>> know" what the role of straw is anyway. Is it there to hold the cob
>>> together while the wall is still wet (like a free form), or to keep
>>> the wall from crumbling incase it cracks later (like reenforcement),
>>> or to allow air/water to move through the wall (because straw is
>>> hollow)? The problem is that nobody knows the reason they used straw
>>> because they didn't leave behind notes on how and why they built  
>>> that
>>> way, and it's been a while since they lived here. What do they do in
>>> Africa? Do they use straw "in" the cob? Can any other plants be used
>>> as tensile such as long grasses? I'm almost ready to start cobbing
>>> but straw is just unavailable in GA right now, and what straw there
>>> is has a very high price on it. I'm not willing to pay three times
>>> the price for it if there's a substitution. I would love to just go
>>> out in the field and get some tall grass if it would suffice. It's a
>>> heck of a lot cheaper!
>>>
>>> Chow,
>>> Damon Howell
>>> North Georgia, US
>>>
>>> _______________________________________________
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>>> Coblist at deatech.com
>>> http://www.deatech.com/mailman/listinfo/coblist
>>
>>
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>
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