HEALTH-CONDUCIVE, AFFORDABLE & EFFICIENT EC0-DWELLINGS WITH LOW CARBON IMPACT
DIFFERENT BIO-MATERIAL ECO HOUSES (STRAWBALE, CLAY, STONE, COB, CORDWOOD, LIMESTONE, LOGS ETC)
Above, a strawbale strucure an evo-village in Israel
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OUR ANALYSIS ON HOLISTIC CIVILIZATIONS AND SUSTAINABLE ECO VILLAGES
Top, an illustration of eco-construction with biomaterial.
ECO-CONSTRUCTION - THE STRAWBALE HOUSE
Strawbale buildings are all the rage in alternative construction today, and with good reason--they are cheap, easy to build, and very energy efficient. Strawbale buildings look similar to adobe, with massive walls, wide window sills and typically rounded corners, but with the added benefit of a higher insulation value. The soft, sometimes curvy edges of strawbale construction can lend a fairy tale look to the finished structures. The fun part of strawbale construction is that anyone can do it. Anyone can help stack the fluffy, oversized bricks in place. Strawbale homes and outbuildings were first developed by pioneers in the Sand Hills of Nebraska where there was lots of straw, but few trees. The early pioneers built houses of sod, up until the late 1800's when baling technology provided the first compressed, string-tied rectangular bales. The next logical step was to stack those bales like bricks to make warm walls. Strawbale buildings from the early 1900's are still in use and in excellent condition today. Due to publicity in the 1980's and 1990's there are now strawbale buildings popping up all over the world--in wet and dry climates, from hot southern environments to chilling northern extremes. Strawbale homes are very well insulated. The orientation of the straw in the bales makes some difference in the insulation value. Bales laid flat (with strings running around the top and bottom) rate about R-2.4 per inch while those laid on edge (with strings running around the sides) rate R-3 per inch. However, the bales are usually wider when laid flat than on edge, giving a higher overall R-value. The bales are slightly stronger too, when laid flat.
From the health viewpoint, roofs can often be covered with earth-humus from which medicinal plants grow and thanks to which rain water can be used for cleaning via aromatherapy. While strawbales can be filled with organic lavander flowers thanks to which the limestone-clay plaster will emanate aromatherapeutic essences during the watchful carresses of solar rays. In this way, the level of energy within the house will be all the more high that the circulating energy is necessarily circulating, given the dome structure thereof. As the American Indians used to say, in particular, Black Foot, "Power is in the circle like with our tipis, not in these energy losing square boxes inside of which you the White Man has placed us".
Other pieces of facts suggest that the benefits of earth sheltering are numerous. They include: taking advantage of the earth as a thermal mass, offering extra protection from the natural elements, energy savings, providing substantial privacy, efficient use of land in urban settings, shelters have low maintenance requirements, and earth sheltering commonly takes advantage of passive solar building design. The earth's mass absorbs and retains heat. Over time, this heat is released to surrounding areas, such as an earth shelter. Because of the high density of the earth, change in the earth’s temperature occurs slowly. This is known as ‘thermal lag.’ Because of this principle, the earth provides a fairly constant temperature for the underground shelters, even when the outdoor temperature undergoes great fluctuation. In most of the US, the average temperature of the earth once below the frost line between 55 and 57 degrees fahrenheit (13 to 14 degrees celsius). Frost line depths vary from region to region. In the USA frost lines can range from roughly 20 inches to more than 40 inches. Thus, at the base of a deep earth berm,, the house is heated against an exterior temperature gradient of perhaps ten to fifteen degrees, instead of against a steeper temperature grade where air is on the outside of the wall instead of earth. During the summer, the temperature gradient helps to cool the house. The reduction of air infiltration within an earth shelter can be highly profitable. Because three walls of the structure are mainly surrounded by earth, very little surface area is exposed to the outside air. This alleviates the problem of warm air escaping the house through gaps around windows and door. Furthermore, the earth walls protect against cold winter winds which might otherwise penetrate these gaps. However, this can also become a potential indoor air quality problem. Healthy air circulation is key. As a result of the increased thermal mass of the structure, the thermal lag of the earth, the protection against unwanted air infiltration and the combined use of passive solar techniques, the need for extra heating and cooling is minimal. Therefore, there is a drastic reduction in energy consumption required for the home compared to homes of typical construction. Earth shelters also provide privacy from neighbours, as well as soundproofing. The ground provides acoustic protection against outside noise. This can be a major benefit in urban areas or near highways. In urban areas, another benefit of underground sheltering is the efficient use of land. Many houses can sit below grade without spoiling the habitat above ground. Each site can contain both a house and a lawn/garden.
Besides strawbale, earth, limestone and clay, there are many other biomaterials. Of these, we will favor bamboo, cordwood, logs and stones from the river. And when possible, build directly into the landscap and the immediate environment, e.g. stone cavern, tree house, using live trees as vertical beams and other techniques.
A DESIGN FEATURES FOR A SMALL STRAW BALE DOME DWELLING UNDER 20,000 DOLLARS
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