Green Home Building and Sustainable Architecture

Sustainable architecture is an exciting and important field, with many people reviving traditional methods of building and others creating innovations to established practices. Kelly Hart, webmaster of the popular website, posts text and photos featuring what he discovers from around the world.

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Location: Crestone, Colorado, United States

Kelly Hart has been involved with green building concepts for much of his life. He has also worked in various fields of communication media, including still photography, cinematography, animation, video production and now website development. Kelly has lived in an earthbag/papercrete home that he built and consults about sustainable building design.

February 24, 2007

A Dream of Floating Cities

A woman recently asked me if I might be interested in reading about a dream she had had about future cities. I was imediately intrigued, and said, "Sure!" She then emailed the following to me.

I had to share this dream with you as I found it so astonishing. I think I saw a city of the future. I was touring it as I was waking and continued to tour it as I slowly came alert. I wasn’t amazed until I was fully awake. Never in my wildest imaginings have I ever come up with something like this. Here’s how it goes:

I was looking, first, at a single structure. It was a globe shape similar to the shape of a Spanish onion, which is a rather flattened sphere. It was attached to the ground by a slender stalk and floated several hundred feet above the ground. It was huge, several hundred feet across, maybe even several thousand feet, and had three levels. The stalk held several elevators and water lines. It attached to the earth by a device that was the opposite to anti-gravitation. It also had “claws” that grabbed into the earth but could also be retracted if the structure required moving.

Each floor had within it an anti-gravitational device which was how it remained safely so far above the ground. The floor was some type of plastic which collected heat and dispersed it slowly. It had carpeting over it, all colors, depending on the preferences of the people living there.

The first floor held the sewage treatment plant which was biologically active in that it treated all sewage and organic garbage produced by the population on the second floor. Methane gas was gathered from the sewage and used to produce heat for warmth and cooking. When the solids from this plant mounted up, they were eventually transferred back to the earth as humus. The liquid filtered and recycled into an area where salad and herbal plants were grown for the immediate consumption of the residents of this structure. The left over water from this section was either recycled again or returned to the earth. I guess there were air recycling machines but I didn’t notice any. The silvery plastic type material covering this structure seemed to breathe and allow adequate air ventilation and there were openings around the outside similar to gills. That’s the only way I can describe them.

The second floor contained the residences and housed several hundred people, most of which were family units. The living areas were pie shaped with what we would call the living room on the outer rim, bedrooms closer in and kitchen, bathroom, and laundry close to the stem. I don’t know if there was any use of live fire in this part, as in candles or fire places. It stayed as warm as was needed from the year-round in-floor heating. This heating could be regulated just as we regulate it today. But still, people do like to gather round a fire or burn candles just for the beauty of live flame. I just didn’t notice whether anything like that was used.

The third floor was relatively open with a large space where the residents could run or walk. The very center had a garden of sorts with chairs and a fountain. The people were driving or I should say, flying some kind of small vehicles that didn’t use any of the current methods of propulsion and I guess were equipped with anti-gravity devices as well. They were very quiet and quick. The same thin, silvery material gave this section a partial roof so that there were places to park all around the edge. But the vehicles didn’t stay parked. If they were staying, they attached to the main structure with similar stems where they floated until they were needed.

Then I noticed that there were some of these huge dwellings that had several of these “bulbs” on one stalk. There would be up to five or six floating one above the other connected by a common stalk. These stalks were fairly pliant and could move somewhat if a strong wind came up.

It was the covering that took a great deal of my interest. There were strong cables, again of some kind of metallic plastic, that made up the stalk and the ribs of the structure. They were covered by a skin of a silver, reflective type of plastic. It reminded me of aluminum but looked smoother. It was amazing in that it breathed. It expanded when the weather was hot and became more breathable, then contracted, becoming quite thick when it was cold, thereby conserving the heat. It also darkened as the day grew brighter, similar to eyeglasses we can get now. The ventilation gills around the outside opened or closed as needed. They appeared to respond automatically to the quality of the indoor air. They even seemed to be filtering the air both coming and going. The whole structure almost seemed to be alive and intelligent. That sounds kind of creepy but it didn’t feel creepy. The whole aura was very benign and comforting.

Then I was seeing a great concentration of these spheres and I thought I was seeing Calgary at some distant time, but the city as we know it now was vastly changed. There were still buildings and houses of the type we know today and certainly, historical buildings had been preserved. However, the urban sprawl that the earth suffers from today was totally eliminated. In its place were farms and gardens, parks and forests.

It was so beautiful and felt so vibrant, like it still does in a deep forest now. And the air! It was as clear as crystal from horizon to horizon and smelled so fresh and pure. I could feel my skin being revitalized as I stood there.

Other than the astonishing shape of these structures and the level of cleanliness of this “city”, life seemed to go on pretty well as usual. There were large structures close to the earth but still attached to a stalk, where goods were bought and sold. More similar structures where people met for theatre or dance or some other social endeavour. There were still ground vehicles similar to what we have now but I saw people on bicycles and horse back or just walking or running. It just seemed that humans had found an answer to urban sprawl and a small area could sustain a very large population without draining the earth’s resources or displacing the natural flora and fauna to the extent we do now.

Oh yes, one more thing I saw. Some of the floating cities could have the mooring stem pulled up. Then they became traveling floating cities. They were a slightly different style with more of a dish bottom so that they could set down on water. They just drifted wherever the wind took them. I wondered how they dealt with a potential collision course with a mountain but I never found out. I guess they could be towed away if needed. I expect they could be towed anywhere as their shape would be conducive to easy propulsion or pulling. They were very beautiful. The entire landscape was beautiful, pastoral and quiet and clean. There were lots of roads but not much traffic. I guess most people liked to use the little flying ships if they were going anywhere very far. Some people “flew” out of their home by parachute or hang glider. I saw them sailing away into the distance just like we see hang gliders today.

I would very much like to work with a graphic artist and illustrate them for email. I am still amazed whenever I think of them.

I know why I dreamed of them. I have been studying and using co-creative science through Machaelle Wright’s work called Perelandra. If you would like to examine what she’s sharing with us, her site is .

These cities almost look as if they were grown rather than made. I don’t suppose that’s so. I expect they were made like everything else we do but we are obviously far beyond what we are doing today. All we really need are anti-gravitational devices. With all the advances, somebody might already have something in the works.

Feel free to ask questions or make comments. Others may have seen them, too. Amazingly, my young granddaughter said they looked familiar to her. How about that???

While reading about this dream I was reminded of some of the imagery that I have seen illustrating the books or stories of Cordwainer Smith, who happens to be my wife's father. I found one of these images and have posted it below.

February 19, 2007

Straw/Cement Blocks

I was asked to review a manuscript entitled "Development of Straw-Cement Composite Sustainable Building Material for Low-Cost Housing in Egypt," which I did below:

First of all, I applaud anyone who is seeking sustainable solutions for building technologies, as these are essential for our continuing health and success as a species. The aspects of the concept presented for manufacturing building blocks from rice straw and cement that I would consider sustainable are:
  • One component (the straw) is a surplus renewable material that when utilized will take it out of the waste stream and avoid possible air pollution from burning it.
  • The straw is free, which lowers the cost of the production
  • The straw-cement blocks can be produced locally by relatively unskilled labor, again lowering costs
  • The resultant blocks provide better insulation values than conventional concrete blocks.
On the other hand these blocks call for a substantial component of Portland cement which is known to be a major contributor of CO2 greenhouse gas into the atmosphere. This cement (along with the straw) must be transported to the building site, which also contributes to effective pollution. And the cost of Portland cement is significant ( I suspect much more than the estimated $1.50 per bag estimated in the paper).
If you compare this proposed technology with the vernacular use of straw-reinforced mud (adobe) bricks that have been used since 4,000 years B.C. (according to this paper), then the newer technology does not appear to be as sustainable. Hassan Fathy has clearly demonstrated the appropriate use of mud bricks in Egypt, especially for low-cost housing. Consider these aspects of mud bricks:
  • Every component (clay, sand, water, straw) is potentially free
  • Every component has little embodied energy
  • These materials are potentially available on site, or locally
  • These building blocks can be used in load-bearing walls, or for other compressive purposes (which the straw-cement blocks cannot)
  • The mud bricks provide nearly as much thermal resistance as the straw-cement blocks (R-1 per inch)...neither of which is very impressive, especially in a hot climate, but at least the mud blocks provide better thermal mass, so under certain circumstances they will perform better thermally.
  • Mud bricks can be "stabilized" with a relatively small amount of Portland cement (or asphalt emulsion) for use in circumstances where a greater degree of durability is required.
  • Mud bricks can be produced with relatively unskilled labor.
In conclusion, if sustainability is to be the criteria for choosing one technology of the other, I ask why introduce a new cement-based product when the older vernacular material (mud bricks) is superior in almost every respect?

February 17, 2007


I have had some comments posted at for several years about "conics" as an interesting concept for making very thin-shelled curved structures without the need for much of a structural framework. Chuck Henderson from Northern California first pointed out how sheets of plywood can be attached to each other and warped to form some very interesting shapes, as pictured here at the left.

Then a few days ago Avi Rotem from Israel sent me a description with some images of models that he has made of conical structures made with steel beams erected as tripods as a basic support for the sheet metal which is then wrapped over this. Avi would then have a substantial layer of sprayed polyurethane foam, polystyrene sheets, or locally used insulation like straw placed over the sheet metal. A final layer of polymer modified cement would then be applied with wire mesh at its center to provide a strong weather-tight exterior coating.

For more information about these systems, visit .

February 04, 2007

The Earthbag Architecture of Akio Inoue

The technique of building with earthbags has been finding adherents around the world. In addition to the experiments of Nader Khalili in the United States, I know of projects in South Africa, Uganda, Kenya, Afghanistan, Mexico, Japan, Cambodia, China and India. One person who has organized many such projects is Professor Akio Inoue of Tenri University in Japan.

The Tenri University International Cooperation Project responded to the 2001 earthquake near Jamnagar, India by sending a group of 15 students and other personnel, including Akio Inoue as the project leader. They stayed for two weeks and constructed a 20 meter check dam (partially with earthbags), and two bongas (earthbag dome shelters with thatched roofs) near the village of Moda. They also planted 1000 young bamboos to use as roofing material to connect three earthbag domes for an elementary school in the Bolachadi village of the north-eastern area of Jamangar. These three domes were completed by subsequent groups of students over the next three years and were used for a library at the elementary school, which had suffered much damage from the earthquakes. These structures measured about 3 meters in diameter and 4 meters high.

Sometimes they hired Indian workers, but also interested pupils and neighbors cooperated in the building when they covered the completed domes with cement stucco. Built-in earthbag benches provide seating for the students. The interior walls were left as white unfinished earthbags.

In Entebe, Uganda, the Tenrikyo Mission Center assisted Professor Inoue and some of his students with building some small earthbag domes, where they used the abundant soil taken from anthills to fill the bags. These domes are being considered for use as refugee shelters in the region, because they provide good protection from bullets, fire, wind, and rain…much better than the conventional thatched shelters or tents. Also, plans are under way for the construction of a Grameen Pig Bank and a church using the earthbag technique.

In addition to the disaster relief work mentioned above, Professor Inoue and his students have constructed 23 earthbag domes of various sizes in Japan, mostly on the campus of Tenri University as a Model Ecological Design Center. There is a lovely precise symmetry and grace to these buildings that is essentially Japanese in nature, which I greatly admire.