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Okay, so now you know just how beautiful earthen architecture can be, how
high in the sky it can reach, how long it can last. At I Love Cob dot com
(no spaces between the words), Minnesotan Michael Blaha has put together a
great two-minute tutorial, a little quicktime movie on the ABC's of cob.
But what about 8-storey adobe, is it done the same way? How do they do
it, how do they build massive mud skyscrapers? What techniques do the
Natural plaster master Julie Haddow joined me for a jaunt across Arabia Felix, determined to discover the secrets of making mud-brick architecture. I am pleased to report that we were granted access to countless building sites and lime-making locations. No, we didn't actually get our hands dirty or try a trowel out for size; but as you'll see in this slideshow, though these labourers produce architectural masterpieces every time, their skill set is a relatively simple one, one that can easily be learned by any motivated mud mason wannabe. And I wanna be!
Once again, I have included images of mud bricks that are fired in the kilns on the outskirts of Sana'a, intended for construction sites in town.The mixing of the mud is pretty much the same in the case of sun-dried adobe bricks. Ditto for the formwork -- the mud is slapped and smeared into the rectangular wooden frame, which is removed immediately afterward, to be filled repeatedly ad infinitum. The bricks are left to dry for a few days, then pried from the earth with a sharp object, and stacked to dry some more, while taking up less floor space, so more mud bricks can be made in the meantime. Notice the difference in size and shape between the clay-fired bricks and the sun-dried variety in the pictures that follow.
The laying of the brickwork is executed efficiently, usually in teams of 3: one man lays the mud mortar, one man puts the brick in place, and the third person is a man-at-arms, he hands the mud mason the next brick, so the assembly line moves seamlessly. I would point out that floors are built in the same fashion, from mud bricks! First wooden beams approximately four inches in diameter (or, in some cases, metal pipes three inches in diameter) are used to bridge the gaps between walls and supporting pillars. Then tiny branches less an an inch in diameter are laid width-wise across these beams; sometimes a woven straw mat is used instead. Finally, several layers of mud brick are packed down on top... and the structures will stand for centuries!
Wooden window frames are inserted directly into the mud, then plastered flush. Pillars are made of stones that are stacked vertically and held together by metal bolts, then mudded over top to bottom to achieve an aesthetic uniformity. Even spiral staircases don't pose any problem with adobe brick, they're no different that any other flat surface, only stepped, made of layers of mud. When it comes to whole floors, the mud bricks are saturated with water from a hose, then smoothed over with large floats; it dries hard and horizontal, like concrete, only better. As you can see, there is no material that can match the mud; in Yemen, the clay reigns supreme!
If you've ever wondered how lime is made, the next set of images tells the whole story. Rocks of limestone, easily identifiable after a quick crash-course in basic geology, are burned in a kiln, then melted down with ordinary H2O, and beaten with a big stick to mix it well. In the kiln, the lime stones are stacked in such a way as to allow the heat of the raging fire to penetrate all the way to the back of the stack, so that all of the lime completes the chemical reaction. Machines with rotary motors have been developed that mix the lime automatically, mechanizing and speeding up the process. Then the lime is left to cure in vats for weeks or months, the longer the better.
Although it is not toxic, only caustic, lime is a relatively expensive product -- for Yemenis -- both economically and ecologically. Fossil fuels must be burned for over 24 hours in order to process the lime. For this reason, it isn't used haphazardly, only where necessary: in the interior spaces, in bathrooms and kitchens; on the exterior walls, only on first floors, roofs, and lining the eaves that run down the sides of the buildings. It may be a costly step, but it's surely more affordable than the unecological alternative. And it's certainly more beautiful: see the last two photographs, with Shibam in the background, what a site to behold.
I don't suggest that you go out and build a skyscraper of your own purely on the basis of this pictorial portfolio. But all my natural builders out there -- holla if you hear me! -- should have a matrix of information to plug these pictures into, should be able to try their hand at these techniques almost immediately. And for the rest of y'all -- get thee to a natural building workshop, toute suite, there's no time to waste, Climate Change has changed the game, the Era of Peak Oil is upon us. We need a new New York made of mud, and we need to do it in community! Thank you to the Yemeni mud masters for showing us the way, now let's clamber up onto the shoulders of these giants, and create a paradise on earth, from earth!
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