Natural Building Techniques

Adobe

Earthbuilding technique using formed and sun-dried mud bricks ("adobes") to create massive walls. Has also been used extensively in the Middle East to create vaults and domes. Appropriate for drier climates because of the nature of forming and drying the bricks.

Cob

Building method using hand-formed loaves of clay/sand and straw ("cobs") to create highly sculptural monolithic walls and other forms, including bread ovens. Excellent source of thermal mass. Easy to do with minimal tools. Labor intensive. Works in moist climates.

Earthbags

The use of soil-filled sacks to create walls. Has been used to build domes and also as foundations for other materials (i.e. strawbales). Sacks are often free. Experimental in nature, currently being tested by ICBO. Excellent thermal mass. Easy, flexible and fast compared to other earth-building techniques.

Earthen Floors

Poured or tamped earth is used to create a floor which can vary in thickness depending on the exact technique used. The floor is left to dry and then coated with a protecting sealer such as linseed oil and beeswax. There are as many variations in technique as natural plasters (i.e. one traditional African method is to create a floor of fresh cow dung and clay which is then coated with ox blood.)

Light Straw-Clay (Leichtlehm)

Technique from Germany which involves coating loose straw with a clay slurry. This material is then compressed into forms in a manner similar to rammed earth. Is used most commonly to in-fill wood framed buildings. Highly insulative, precision walls. Slow drying. Can be used to create lightweight insulating bricks and ceiling tiles. Wood chips can be used instead of straw for a system which can be poured into forms.

Living Roof

Placing organic material over a roof membrane which then supports plant life. Very beautiful. Adds insulation value. Most appropriate in moist climates. Membranes are usually artificial but layered birch bark has been used traditionally in northern Europe.

Natural Plasters and Finishes

Using materials such clay, sand, and straw with binders as varied as linseed oil, blood, manure, glue, lime etc. to create breathable, non-toxic plasters and finishes with differing properties (hardness, workability, color etc.) Infinite recipes from around the world. Plaster (or another form of protection) is necessary to finish off several of the listed techniques (straw bale, earthbags, light-clay) Very "soft" and friendly as compared to cement stucco. Exterior plasters need to be maintained regularly, but are, in the long term, more effective in protecting earthen structures than cement-based plasters.

Rammed Earth

Wall construction method which entails placing slightly moistened soil into forms which is then compressed in layers to create a monolithic wall. Possible to make very precise walls which do not need further finishing. Can be very "high- tech" and machinery intensive, though it historically been done with very simple tools and materials.

Stone, Brick and Wood

Familiar building materials which are very "natural" if used appropriately. Key: use local resources with minimal processing.

Straw Bale Construction

Blocks of compressed and tied straw ("straw bales") are used to build walls that are load-bearing (Nebraska-style) or to create infill walls in non-loadbearing structures. Fast and easy wall-raising system which lends itself to community involvement. Very high insulation value (R-35-50).

Thatch

Roofing technique where reeds, grasses or palm fronds are sewn onto a framework of wood or bamboo to create a water shedding protective covering. Highly skilled thatchers can create roofs which will last 50 years.

Tires and other Recycled Materials

Technique popularized by Michael Reynolds ("Earthships") which involves using soil-filled tires as building blocks, as well as aluminum cans and old bottles. Wonderful way to use up these (often free) materials which pollute so many parts of the world. High thermal mass. Labor intensive.

Wattle and Daub

Earthbuilding technique which utilizes a woven wooden or bamboo frame as a form onto which mud plaster is applied in layers until the desired wall thickness is reached. Probably the most ancient of earthbuilding methods.

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