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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Name: Kelly Hart
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 (but is now mostly living in Mexico) and consults about sustainable building design.

April 27, 2006

Messages from Mesa Verde

I visited Mesa Verde in Colorado near the Four Corners. This was my first encounter with the “ruins” of the ancestral Puebloan people, progenitors of the Pueblo and Hopi nations. I had heard about Mesa Verde since I was a kid, but nothing could prepare me for the awesome reality. Despite the influx of tourists, there is a peaceful and spiritual quality that persists.

The most famous aspect of what was left behind there are the cliff dwellings, which are certainly magnificent. These finely crafted rock structures emerge from huge alcoves within the cliff faces, and from a distance resemble swallows' nests, fitting into the surrounding rock just as naturally. Actually the cliff houses represent the culmination of about seven centuries of habitation at Mesa Verde. Then around 1300 AD the people abruptly abandoned their homes and moved south and southeast to establish other communities. There is much speculation about why they moved, but the most likely cause was a prolonged period of at least 12 years of drought.

The cliffs were only occupied for the last two centuries at Mesa Verde; before that, all habitation was on the mesa above. At first the people made rectangular pit houses that were dug partially into the ground and then built up with poles and sticks plastered with mud. The entrance was via a hole in the roof with a ladder descending to the floor below. Archeologists believe that from this simple pit house both the freestanding masonry pueblo and the underground circular kiva evolved. The cliff dwellings combined both interconnected pueblo “apartments” and kivas, which were used for ceremonial and community functions. Some of the larger cliff dwellings may have housed over a hundred people. Most of the Mesa Verdeans lived in this communal way, but there were also many smaller housing units scattered throughout the area. It is obvious that they were a very cooperative society.

Little did they know that their style of architecture would become so enormously popular many centuries later. “Pueblo” or “Santa Fe” style building can be linked directly to them. The Spanish introduced modular adobe blocks that make the construction go faster, but the simple stacked rectangular shapes with protruding vigas is native American.

These people were primarily farmers, growing squash, corn and beans in terraced garden plots on the mesa tops. They carefully guided water to their gardens. The mesa itself slopes gently toward the south, which improves the solar gain for gardening, and the colder air slides down the canyons and off the mesa, which increases the growing season.

There is a lot of speculation about why they decided to start building communities within the cliff faces. Some think it was for defensive purposes, although there is little evidence of violence to support this. My sense is that they moved to the cliffs for comfort. Some enterprising individual or family probably tried building a stone house on one of the many cliff ledges that faces south and soon realized that there were many advantages, which were pointed out to the others. Sealing off a cave or cliff alcove with rock walls effectively makes the room a part of the cliff itself. It's like digging into the ground to take advantage of the cool in the summer and the warmth in the winter, but under the rock ledge they were also protected from the rain and snow and had much more thermal mass to buffer temperature extremes. Facing south, or southwest, as many of the cliff dwellings do, would allow the sun to enter the openings into the interior and also warm the stones, which would give off heat at night. During the summer, when the sun is high in the sky, much less sun would reach the buildings and they would remain cooler.

To read the rest of this article, please go to this page at

April 18, 2006

Heating with the Sun

Using the sun to heat your house has got to be the most economical and ecologically benign way to keep comfortable when the temperatures drop. There are a number of common strategies for doing this. My favorite method is passive solar design, where there are no “active” fans or pumps to contend with. Most passive solar designs are basically invisible, because the room itself is the collector. It performs well because the design of the space and the choice of materials to build it cooperate in keeping the space comfortable.

The basic concept is to use south-facing windows to allow the winter sun to enter the room, and then store the heat from that sunlight in some thermal mass material, so that the heat can be given back at night. Enough solar energy should enter the room on a sunny day in December or January to maintain a temperature of about 70 degrees F. for the 24 hour period. If the space overheats, then there is either too much glass, or too little mass. Or if the space isn't warm enough, then there is either not enough glass or there is too much mass. Slightly oversizing the design can compensate for some overcast weather.

Here are some guidelines for good design: at 8,000 ft. in Colorado use about 35% of the square footage of the floor space in any given room in actual window area. At lower elevations or more southern locations, the percentage of glass should be less. These windows can be oriented up to 25 degrees east or west of true south, and still collect over 90% of the solar energy. Interior walls and floors should have at least 4 inches of masonry material lining them. Use dark colors for the floors, and don't cover them with carpeting. Walls can be any color.

The interior thermal mass (brick, adobe, concrete, tile, rock, etc.) needs to be insulated well from the outside environment, or else that stored heat will just leak out. Straw bales, scoria (crushed volcanic rock), and wool are good natural insulating materials. The floor should be insulated, as well as the walls and ceiling. Glass is a poor insulator, so when it gets cold at night, insulating curtains or panels need to be used in the windows to hold in the heat. Windows on the north, east and west should be minimized to help with insulating the house.

How do you keep the rooms from overheating in the summer? Again, good design will take care of this problem. One approach is to have deciduous trees or vines shade the south side. Architecturally, summer shades can be built into the design. By simply having the eaves of the roof extend far enough beyond the sides of the house, most of the summer sun can be eliminated. This works because the sun is much higher in the sky during the summer. Another approach is to have thick walls. A 20” wall will keep out most summer sunlight. Unfortunately, there is often a lag in the heating of the seasons, so that as Fall approaches and the sun begins to lower again, the earth has absorbed much summer radiation, and it can be quite warm. So to avoid too much sunlight in the Fall, it may be necessary to shade some of the windows during the day.

To read the rest of this article go to this page at

April 16, 2006

Small is Beautiful

Why build and live in a small house? First of all, it is more convenient to have what you need nearby. Life proceeds smoothly when the things you need are close at hand. Also, I might point out that limited space forces you to select only those things that you really need to live with, helping to keep clutter out of your life.

Another fairly obvious point is that a smaller house costs less to build and maintain. Housing represents the greatest expense that most of us face in this life. It is common to take on huge debt to pay for a house, which multiplies the cost even further, and places us in a kind of servitude to both the creditors and the house. Rob Roy, in his book “Mortgage Free!,” points out that the word mortgage comes from old French, and means “death pledge.” In it he describes many ways to build without debt. If you are able to own your house free and clear, all those years of your life that would have gone into paying off the debt can be utilized to positively affect your life and the world.

Obviously, the smaller the house, the fewer resources are consumed in creating it. Since the use of many building materials has a negative impact on our environment, keeping it small lessens the impact. Then there is the environmental cost of heating and cooling a house to consider. The smaller the house, the less this cost will be. Burning fossil fuels, either directly (such as propane heating) or indirectly (such as heating or cooling electrically), consumes these finite resources and contributes to carbon dioxide pollution. It is much easier and more effective to design a solar heated house that is small.

Another impact to consider is aesthetic. Does the house fit in with the landscape? A large, imposing edifice may seem out of scale with the surrounding land, whereas a small abode is more likely to fit in nicely.

To illustrate some of these concepts, Suzanne Frazier has graciously allowed me to use her home as a model “small house.” Built in 1994 by “Cut No Slack” construction of Salida, Colorado, Suzanne's house is more or less conventional in materials used (wood framed, etc.). She wanted it to conform to the Uniform Building Code so that she would be sure of its integrity as a house over time.

To read the rest of this article please visit this page at

April 13, 2006

13 Principles of Sustainable Architecture

As “consumers” we are frequently confronted with life style decisions that can impact our environment. There are a few choices in this life that can make a big difference in what the quality of life will be for those who follow us. Going with the flow of our culture is hard to avoid, and unfortunately the flow is not in the right direction for evolving a sustainable future.

One of the most momentous choices that any of us will make is the kind of house we live in. I have come up with a list of thirteen principles of sustainable architecture that can guide you in your housing choices.

Small is beautiful. The trend lately has been toward huge mansion-style houses. While these might fit the egos of those who purchase them, they don't fit with a sustainable life style. Large houses generally use a tremendous amount of energy to heat and cool. This energy usually comes from the combustion of fossil fuels, depleting these resources and emitting greenhouse gases and pollutants into the air. Also, the larger the house, the more materials go into its construction; materials which may have their own environmental consequences. A home should be just the right size for its occupants and their activities. My wife and I (and our two dogs) have happily lived in a forty foot bus for the last four years. The key to this is efficient use of space, good organization, and keeping possessions to a manageable level. We do look forward to spreading out some in the passive solar, earthbag home we are building.

Heat with the sun. Nothing can be more comfortable for body and mind than living in a good solar-heated house. I say “good”, because proper design is crucial to the comfort of such a house. You may have gone into a solar house and felt stifled by the glaring heat, or perhaps you shivered from the lack of it. Good passive solar design will provide just enough sunlight into the rooms to be absorbed by the surrounding thermal mass (usually masonry materials), so that the heat will be given back into the room when the sun goes down. The thermal mass is a kind of “heat battery” that stores the warmth, absorbing it to keep the room from getting too hot during the day. Equally important to thermal mass is insulation (such as straw bales or crushed volcanic rock) that will keep that heat inside. Thermal mass materials need to be insulated from the outside, or else they will just bleed that warmth right back out. A rock house might have tons of mass, but be uncomfortably cold because of this energy bleed. So a good solar design will utilize materials of the right type in the right places, blending thermal dynamics with utilitarian design. There is much more to be said about solar design, and there are many good books on the topic.

Keep your cool. As I suggested above, a well designed solar house is both warm when you want it, and cool when you want it; that is to say, the temperature tends to stay fairly even. A good way to keep your cool is to dig into the earth. If you dig about six feet into the earth, you will find that the temperature there varies by only a few degrees year round. While this temperature (about 50-55 degrees F.) might be too cool for general living comfort, you can use the stability of the earth's temperature to moderate the thermal fluctuations of the house. If you dig into a south-facing hillside to build, or berm the north part of the house with soil, you can take advantage of this. The part of the house that is under ground needs to be well insulated, or the earth will continually suck warmth out of the house.

To read about the last 10 principles, please go to this page at

April 11, 2006

Poured Earth

I have created a new page at about Poured Earth, which is similar to ordinary concrete, in that it is mixed and formed like concrete and uses Portland cement as a binder. The main difference is that instead of the sand/gravel used as an aggregate in concrete, poured earth uses ordinary soil (although this soil needs to meet certain specifications) and generally uses less Portland cement. Poured earth could be considered a "moderate strength concrete." Little to no maintenance is required of poured earth walls, since they have a high resistance to the deteriorating effects of the weather.

I have featured this page rather than the Cast Earth page I had featured earlier, because the process is much more user-friendly. Cast Earth is a patented, proprietary system (using quick-setting gypsum as a binder) that really must be accomplished by a crew trained by the inventor. Poured Earth, on the other hand, can be handled by anyone familiar with the pouring of ordinary concrete, and who is willing to make sure that the ingredients meet certain standards.

I am pleased that earth-pouring expert,
Michael Frerking, has agreed to answer questions from the public about this method of building.

You can read more about this at