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Learn Vault Building — 4 Comments

  1. This is a true nubian vault.

    The key to this design is that the long vertical side walls are thick enough to act like buttresses for the roof. Those walls not only hold up the large weight of the roof, but those walls also prevent the roof from spreading out horizontally. This is critical because if the walls bow outward and allow the roof to spread, the roof will fail. It’s a great design when built properly.

    The string compass is a short-cut to approximate a catenary curve. The catenary is the ideal curve to use in a vault because it assures that all the bricks are in compression. None of the components are asked to withstand any tensile (pulling) forces. Since earthen bricks are very strong in compression and rather weak in tension, this is absolutely necessary for the design to work.

    A more perfect catenary curve can be created by hanging a chain from two points the same distance apart as the support walls. The chain will curve downward, and drawing that curve onto a template (made out of scraps of wood and cardboard, or whatever else might be laying around.) That template can be rotated 180 degrees and placed against the leaning wall to trace the catenary curve.

    Keep in mind that the larger the span of the roof, the larger the forces become, which means that little imperfections which may be insignificant on smaller spans can create massive problems on larger spans. The bigger the span, the more perfect every aspect of construction must be. THAT IS WHY NUBIAN VAULTS DO NOT SCALE UP IN SIZE VERY WELL.

    I don’t recommend that an amateur attempt a nubian vault wider than was shown in the video without getting the assistance of a qualified engineer.

    If someone desires twice the space, do what the Nubians did thousands of years ago. Build a second vault, or build the structure twice as long.

    However, small spans are very reasonable for an amateur to attempt.

    As always… start small. Try a small nubian vaulted shed first. Learn and make mistakes on a small building first where the risks are smaller. Move on to larger structures when you have confidence in your abilities… keeping in mind that larger spans must be built with greater accuracy and care.

    Here are a few helpful links that help explain how nubian vaults like the one shown in this video are constructed.

    http://www.earth-auroville.com/maintenance/uploaded_pics/2b-voute-nubienne-en.pdf

    I hope this following link works. I used google translate to put it in english.

    http://www.google.com/url?sa=t&rct=j&q=nubian%20vault%20construction&source=web&cd=15&ved=0CDkQFjAEOAo&url=http%3A%2F%2Fwww.unhabitat.org%2Fpmss%2FgetElectronicVersion.aspx%3Fnr%3D1774%26alt%3D1&ei=EWSWUMDmNork2QWIzIDIBA&usg=AFQjCNFy6kDLKgyU_6fIF2whIow-O10Ahg&cad=rja

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