I know the Island of Haiti is dealing with a huge demand for new houses that will take the hurricanes and, now, the earthquake tremors, so I began to think about the shape of the egg.
I was at a seminar on sustainable housing that uses clay, gravel and cement, all easy to get and most areas of the world do have them all. This was the beginning of an idea that would possibly work in Haiti, because it is intensive in manual labour, does not require machinery or rebar, and would be much stronger than the brick and mortar they now depend on.
The shape of the egg is remarkably stable. The question then became more of the techniques and means to build houses that were using this shape, and, at the same time, not require a huge amount of engineering expertise or imported materials. So I connected the two ideas, but how to make this structure without using wood or steel, both prohibitively expensive for anyone other than the rich in Haiti.
Churches gave me the answer. Ribs! I have seen domes in churches hit with bombs, and yet the only damage was to the area where the bomb went through, but the structure stayed strong.
So, I thought on how to design this with a good sustainability and keep the water from causing more mud slides and ruining the hills. Cup and Saucer!
Put the house on three points of support that are dug deeper into the earth, then build the walls, 2 feet straight up, then curving up to the dome. Add some perimeter walls or surface that is slightly dished in the middle, and the rain should run into this. Now, what to do with the rain?
Drip system that would water trees, gardens and provide a means to control the runoff, without creating a huge mud slide.
Now to the needs of the inhabitants, which would present a challenge. Light…. where would that come from without causing a fault in the dome or provide a weakening of the walls? Several options came to mind here. Fibre optics transmit light, but that would be expensive in Haiti. What would be a feasible substitute? Glass rods….. possible. Tubes set into the wall with glass shards, but that would require a means to seal up either end of the tube. Hmmm well, I know that old car windows are made of tempered glass, as are the covers for signal lights, etc. These would require setting into the walls as the walls rise, but a possibility.
The walls themselves are labour intensive, can use the rubble and debris, and would become something far better for the people. How are the walls made?
Two ways to mix the material. One is simple cement, combined with clay and small gravel or debris, to a consistency of dry cookie dough. It will clump slightly, but is not a fluid or the standard concrete slurry that most people know. The second way is to use steel fiber reinforced concrete, which would be good for things like orphanages and larger structures, but expensive for the average house.
How do the walls go up? Forms, basic forms made of scrap wood, metal, that are bent to the curve in the wall. These are set at the base, and the “feet” of the house are dug below the ground to use as anchors, which may not really be necessary, but still would stabilize the structure, especially on a hillside location.
The material is mixed to a crumbly consistency, then put into the forms. After that, either a person using a pole with a flat piece on the bottom (a tamper) or a similar mechanical means are used to pack the material. I have seen these walls used to build houses in an earthquake zone, and, while done vertically, they have passed the codes for housing. The curves are the stronger shape.
Walls can be built with this method, and they have been used as small versions of retaining walls.
Now, to get fancy here. Windows…… how to put windows into the structure without defeating the whole purpose? Triangles! Placement of triangular windows that are next to the interior ribs would be structurally strong enough to withstand hurricanes and earthquakes, as long as the glass was put into either a frame that had some “give” or were from such things as old car windows (tempered glass) and aligned with the outer surface. This would avoid the vortices or any other possibility of wind damage.
Sewer or waste water would have to be removed, so this would require either an interior means of disposal or the use of some kind of disposal that could be connected using either earth (think outhouse) or a cistern that would work something like a septic tank but with an outlet to a place where plants that absorb toxic and fecal material are planted. There are several examples of this worldwide, so the plants would need to be indigenous to Haiti or tropical plants.
The sustainability of these houses would require trees and bushes to be planted around them, to both stabilize the earth and to absorb rain. Gardens could be either container gardens, which would be far more efficient use of the land and much easier to provide for each house, or small areas that are walled in, to prevent damage from the severe weather.
The design would make for 270 degrees of solid walls, with the remaining 90 degrees open for doors and other exterior use. Ideally these houses would be set so that the prevailing winds come from the “back” or the side of the house, so that the hurricane strength winds would be dealt with by the house itself.
Curves are far more stable than almost anything else, and using the material at hand is far better than importing it. These houses can be built using very basic knowledge and training, which means that the Haitians themselves could do this. I do NOT want, in any way, to encourage some multi-national company to exploit the people more, when these houses are available!
I did NOT put the recipe or mix specifications in this article. But, the debris, the rubble, the clay, the gravel and cement are all available.
Ninemoonjupe's Weblog 