Using ferro-cement (iron and cement), or nylon-cement (nylon fishnet and cement) one can make domes and tunnels that are functional and esthetically more natural-looking than boxes are. As tunnels and rooms grow on and around each other, the structure starts to look like the nests made by termites.
The same iron rebar framework that supports the cement can support the growth of vines, which provide shade and food here in the tropics. Global warming and an era of agricultural failures may be on its way. Shade and food are good. The trellises can be converted into cement structures later.
Using examples from two houses I have built, this instructable will show how to get started today on a termite nest city of tomorrow.
Step 1: Materials
To build a termite nest city, you will need a lot of sand and cement. Iron rebar is used to define the basic forms. Chicken wire, or nylon fishnet covers the rebar form and provides a fine enough mesh for plastering with cement. The cement to sand ratio is the standard 1:3 mix used for plastering.
Since iron rusting is a problem with the rebar, longevity is improved by painting the rebar first with a good primer and rust preventative paint. If cost was not a factor, one could use stainless steel, or perhaps something like Cor-ten steel, which forms an oxide coat that protects from further oxidation. It would be ideal to use immortal materials, so that a city could keep growing without ever having to use demolition on the old parts.
The old parts of the city, at the bottom, would be protected from the weather by the younger parts above them, improving their longevity.
Step 2: Painting the Rebar
The rebar goes in one end of the pipe, passes through the paint reservoir and comes out the other end painted.
A conical silicone rubber tip, formed over the conical tip of a silicone cartridge is trimmed so that the inside hole is just the right size to scrape off excess paint and keep it inside the paint reservoir.
Step 3: Termite Nests
Termites build their nests out of a paper-like substance they produce. They cover their trails up the sides of trees, like tunnels, to protect themselves. The nests in the trees are irregular, globular masses with this foam-like structure.
A termite nest city would grow over time, layer upon layer.
Step 4: Design Considerations
Domes are very strong shapes since all the parts of the dome are under compression and cement is strong in compression. Cement is relatively weak under tension, such as on the bottom side of flat roofs. Flat roofs need internal walls or columns to help support them. Dome roofs do not.
A termite nest city might grow as a series of concentric domes, with the spaces between the layers filled with free-form construction like termite nests.
Because domes are self-supporting outer concentric layers would not necessarily crush inner layers.
Step 5: Underground
I dug the vertical shaft first, plastering it with a layer of nylon-cement. Then, after doing a lot of measuring and calculations I started in the hillside with the horizontal tunnel and connected with the bottom of the vertical shaft. The tunnel has good ventilation and electricity for lights.
It gets pretty humid in rainy season, but cement and nylon are both compatible with water.
Right now, I am in the process of colorizing the tunnel with colored cement.
Shapes such as stairways, walkways, ponds and furniture can be carved into the earth and covered with a layer of nylon cement to preserve their shapes.
Step 6: Water
A friend years ago told me that cement water tanks keep the water tasting fresher than other materials do. Personally, I get my drinking water in gallon jugs from a local spring because I don't like the chlorine and other additives in public water. Our public water goes out frequently, so it is a good idea to have some in reserve for all the other things we use water for.
Step 7: Trellises
A rebar trellis is basically the same thing as the rebar that defines the form of a cement structure before plastering it. Here in the tropics, vines grow all too well, along with the rest of the weeds. They all provide shade for structures below them, and some vines provide fruit or edible leaves. What with global warming and possible food shortages ahead, shade and food are good things to think about.
Step 8: Doors
Doors can also be made out of cement. They are about as strong as the walls. My doors weigh around 600 pounds and are built in place.
Step 9: Think Outside the Box
Step 10: Interior Shots
Since floors are often domed, or at least sloping in this kind of architecture, it is useful to sometimes hang things, including furniture from overhead. This helps keep the floor easier to clean, for one thing.
I try to keep water run-off in mind always, to avoid puddling. All of my floors and patios slope some so they can be cleaned off with a hose. As far as house keeping goes, I tend to admire the lion pens at the zoo. Just get out the hose.
Step 11: Random Shots
Step 12: Some More Thoughts
Cities have already arisen. They spread out sideways, for the most part. They occupy a lot of territory that would otherwise be wilderness. They have covered a lot of otherwise good agricultural land, too. Maybe they could be condensed some.
I live on a mountaintop, surrounded by nature. The valleys tend to be the places where most of the cities were built, on top of the best alluvial soil. I imagine the topsoil is thinner at the top of the mountains. There would probably be less topsoil sacrificed by building cities on top of mountains than in the valleys.
Perhaps, we could use the tensile strength of steel to hang lighter, foam-like architecture off the sides of ridges, instead of using deep foundations to support skyscrapers from below. Structures might hang on ridges like saddle bags hang on a mule.
We have built our cities, and it is difficult to erase them now. We can use them as scaffolding, however, to build the next-generation of cities over top of them. My house uses what I call nylon-cement construction techniques. Ferro-cement uses rebar and wire mesh to support plastering with cement.
I substituted the wire mesh with free, discarded nylon fishnet from the tuna fishing industry. With nylon-cement construction techniques I can make free-form, dome-like architecture, toilets, washing machines, and lots of other useful things. The material is relatively inexpensive, and long-lasting. It makes a little material go a long way.
I grew up in times excited by Buckminster Fuller and the idea of domes. Science fiction space cities were dome-shape. Transparent domes kept out alien atmospheres. Anyway, domes are cool, and they have some interesting architectural properties.
Complex curvature gives strength. It is not easy to crush an egg shell, considering the amount of material involved. Breaking a flat cracker is relatively easy. Our existing box architecture is all made of flat crackers. I suspect that domes would hold up better in earthquakes and hurricane winds than flat architecture would. Domes also give one the maximum amount of volume with the minimum of material, compared to other shapes with the same wall thickness.
The stress forces in domes are all compression forces, whereas flat floors and ceilings have tensile forces involved, especially on their under sides. Domes can support a lot of weight without any internal supports. Box architecture tends to need support walls and columns.
Let’s cut to the chase. A city could grow as a series of concentric domes. Theoretically, no dome needs to be supported by the domes underneath it. One dome can serve as scaffolding for building the next dome over it, or it could support a layer of light architecture between it and the next dome. The fill layer could be a foam-like structure resembling a termite nest. One could forget the domes and just build with the fill layer, but working the strength of domes into the design periodically doesn’t seem like a bad idea.
We have termites where I live. They cover their trails up the trunks of trees with a paper-thin layer of material they produce, and build a globular nest of this material up in the tree. If you cut open one of the nests, you find tunnels going everywhere. It is like an ant nest with tunnels and rooms.
Expand the termite nest to human scale and you get something like the architecture I have been developing, mostly with domes and arches. For the most part, I have felt pretty safe while doing my construction work, even high up in the air. Very seldom have I needed a ladder to do the work.
My cement house uses a domed grid of rebar to support fishnet. The fishnet has a fine enough mesh to hold cement plastered onto it. After plastering both sides, the resulting wall is about 1 ½ inch thick.
The same grid-like rebar structure that supports the fishnet and cement can be used to make vine trellises to cover it. The trellises shade the house and provide me with fruit and edible leaves. They could be converted into more cement house in the future by removing the vegetation and plastering the trellis with fishnet and cement. In that way, an apartment house, or termite nest city might grow over time little-by little, according to need.
I live in a tropical climate. In a colder climate, the vine idea might not be practical, but it is still the same sort of trellis that is involved in construction of domed cement structures.
With masses of people living together, one needs good ventilation, water drainage, waste disposal, and other things. All of those are fairly easy to design into things given the flexibility of this non-boxy architecture.
Besides designing functionally, this construction technique can also be used aesthetically, like sculpture. Cities could be more like Disneyland and less like Costco, if we stopped building so many boxes. They could be a lot more fun to explore and live in. The more time we spend inside the mall the less time we spend trampling the wildflowers outside the mall.
It is hard for me to imagine something like a termite nest being owned other than cooperatively. If it is the only game in town, who do you trust to be the landlord?
Public transportation might be worked into the structure, something like a subway system. Winches or ski lifts might take the place of truck roads for getting people and things up the mountains. Gravity slides and pipelines could take things down the mountain. We have sure scarred up a lot of the landscape with roads. I wonder when that will stop?
Population control by legislation is not a popular idea in democratic societies at the moment. Maybe we will stabilize at so many billions someday, maybe not. The reproductive rate and death rate are the two factors that need to be balanced. Any stress on the environment changes it. How much stress is too much stress? Minimizing the stress seems to have some importance to environmental health. We have to think about protecting nature from ourselves.
I wouldn’t want to live in any of today’s cities, but there are city people who learn to live with and even love cities. If we are going to continue with cities, let’s think about ways we might improve them. The termite nest city is a whole new ball game.
Step 13: Links
These are links to some of my other instructables. They all have potential uses in a Termite Nest City.