NATURAL BUILDING COURSE Topics
Natural Building is a building philosophy, it relies on materials and techniques which are ecologically sound, culturally sensitive, reliant on local resources and skills, and are within economic reach of local inhabitants, for affordable shelter. Natural materials are an alternative to toxic substances which have led to widespread environmental illness. Those seeking to simplify their lives can build their own homes using such techniques, with community help and local, inexpensive materials. All the methods listed here will be discussed, pluses and minuses of each, overall practicality, best climate, geology and geography for each, during the course. A limited number will be hands on experience. What you get: accommodation, 3 meals a day, WiFi, access to book library, many videos on Natural Building, hands on experience in some methods.
Adobes are sun-dried mud bricks stacked with a mud mortar to create thick-walled structures. These thick earthen walls provide what is known as “thermal mass” which helps to modulate interior temperatures by absorbing excess heat during the day and slowly releasing it at night.
Bamboo is the largest of the grass family of plants. It grows very quickly, providing renewable material for building, tools, and utensils as well as edible shoots. Common in the tropics, many species of bamboo grow in temperate climates as well. Strong and beautiful, bamboo has seen a recent resurgence in popularity with builders.
Cob is an ancient technique of building monolithic (meaning “all one piece”) walls using “cobs” of moist earth and straw that has similar thermal properties to adobe and rammed earth. It is being rediscovered as a multifaceted building material applicable to a number of conditions. Virtually unknown in North America, cob was reintroduced by Welsh architect and permaculturist Ianto Evans, who started the “Cob Cottage Company” with his wife Linda Smiley after intense interest in his $500 self-built cob home.
Compressed Earth Blocks
Compressed earth blocks are similar to adobes, with the main differences being they are not fully saturated with water, are more dense than adobes, and are usually significantly more uniform. These blocks are created using a variety of machines. Some, like the Cinva-Ram invented in South America, use human labor and are relatively inexpensive. Expensive fuel-powered machines, on the other hand, can produce thousands of bricks in a day.
A technique traditional to Northeast America and other heavily forested areas is the use of small lengths of wood as a masonry unit mortared with a cement-based mortar. An insulation layer of sawdust is used between the inner and outer mortar layers. This construction technique has been most prominently advocated here by Rob Roy, who has built a number of houses and saunas using the technique.
Earthbags or Superadobe
Earthbags are soil-filled fabric sacks or tubes used to create walls and domes. Commonly used for flood control and by the military to create bunkers, this method of construction has been recently turned to a variety of natural-building purposes. This technique has been used by Gernot Minke of Germany and is currently being pioneered in the U.S. by Persian architect Nader Khalili of the California Institute of Earth Art and Architecture (Cal Earth), who has dubbed the technique “superadobe.”
“Earthships” are the name for the independent living structures utilizing passive-solar design and recycled materials developed by Michael Reynolds of Solar Survival Architecture. While not exclusively reliant on “natural” materials, Earthships replace some conventional materials with recycled trash which is found all over the planet.
Leichtlehm (literally “light-loam”) is a German technique of coating loose straw with a clay slip and tamping it into forms as an infill for timber-frame structures. This technique was introduced to North America by Robert Laporte, a Canadian timber-framer, and by Frank Andresen, a builder with extensive natural building experience in his native Germany.
Hemp and Other Fibers
Hemp and other fiber-producing plants as kenaf and sawgrass are currently being investigated as potential building products. Commonly used for numerous purposes before drug laws made its cultivation illegal, non-psychoactive hemp is being rediscovered as a source of fiber, oil, and hurd; these can replace less ecologically sound wood or petrochemical products in a variety of building applications.
Rammed earth is an ancient earthbuilding technique currently undergoing a renaissance in the U.S. and abroad. It has been revived in France by CRATerre, in Australia by Giles Hohnen and others, while its main proponent is the U.S. is David Easton, author of The Rammed Earth House. Usually more expensive than conventional construction,this technique has been updated with improved engineering, sophisticated forms, and innovative design to make rammed earth competitive with conventional construction, even in earthquake-prone California. While rammed earth is in limited use in the U.S., builders in western Australia have captured up to 20% of the housing market in many areas.
Straw Bale Construction
The use of baled straw to create superinsulated walls has become an extremely popular method of construction in recent years. Most common in North America, bale buildings have been built around the world. Originally used by the pioneers of the Nebraska sandhills, straw bales are cheap to buy and easy to build with, lending themselves to “barn-raising” parties, where structures and community are created at the same time.
Wattle and Daub
The technique of weaving branches (wattle) as a support for mud plaster (daub) is perhaps the oldest of earthbuilding techniques and is still used for traditional architecture in many parts of the world. Uncommon in the U.S., it can be used in mild climates to create thin earthen walls, but lacks the thermal mass or insulation desirable in other climates. An intriguing use of wattle and daub is to create interior partition walls, with a recent experiment using pulped paper to replace the daub. Michael Smith has recently created inner and outer wattle and daub walls which are filled with an insulating straw-clay mixture.
Wood is an ideal building material: strong, easily worked and beautiful. Its major disadvantage is that its use is unsustainable, with current clear-cutting practices leading to widespread deforestation. Natural builders are seeking alternatives to conventional stick-frame construction, where wood is used indiscriminately, and have begun to use wood in new ways
The Archibio architecture group in Quebec as well as rammed-earth builder David Easton, have updated the ancient sod roof of Europe with a concept called the “living roof.” This type of roof has several advantages: it is an aesthetic feature, helps the house blend into its environment and provides climatic stabilization. While it is particularly useful in wet snowy areas, it has limited applicability in dry climates.
Natural Plasters and Finishes
Before the advent of portland cement, most earthen and masonry structures were protected by mud- or lime-based plasters. While still common in other parts of the world, lime and mud plasters are relatively rare in the U.S. The advantages of these plasters include breathability, softness to the touch, aesthetic qualities, workability and easy reparability, as well as economy of materials. Because they can erode unacceptably in wet vicinities, exterior mud plasters are generally used in drier climates or with wide overhangs.
The use of tamped or poured earth mixtures to create floors is currently undergoing a renaissance in the Southwest U.S. These floors can provide an excellent source of thermal mass in passive solar designs. Methods range from the African use of fresh cow dung sealed with ox blood, to earth mixtures sealed with linseed oil and beeswax.
Natural building is increasingly accepting code- approval such as cob and earthbag construction. These methods are becoming more established, as is rammed earth, adobe and straw-bale. As techniques evolve and more builders, architects and developers employ them, structures which meet human needs while assisting in the regeneration of the planet will become more common. While many challenges lie ahead, it is still a hopeful and exciting time to be part of this quest to create a sustainable human culture.
Acknowledgment to Joseph F. Kennedy – architect