I recently attended a natural building work shop held at M.U.M.’s new sustainable living center, hosted by owner of SunEarth Construction, Keith Lindauer. Keith began his natural building career in 1994, with construction of his first Earthship.
Earthships are off-grid, passive-solar homes made of natural and recycled materials, like aluminum cans and old tires packed with dirt; this thermal mass construction creates temperature stabilization. Earthships are also equip with their own ventilation and water treatment systems, and can be designed to optimally function in any climate.
Keith now specializes in Earth and Lime Plaster; which is primarily what the workshop centered around. Earth plaster (also known as clay plaster) can be applied to just about any surface–from straw bale to dry-wall, and can also be made into bricks.
To make a batch of Earth Plaster, simply mix 2 parts coarse sand with one part clay, add water (small amounts at a time) and stir until you have a soft, sticky, wet consistency. Things like wheat paste, cow manure, and straw choppings (no longer than an inch) can be added for extra strength and binding. This is a durable material, but should be kept fairly dry. In wet, humid regions it is best used for interior walls.
To make Lime Plaster, mix two parts coarse sand with one part lime (Type “S” is recommended), add water and stir until you have a consistency like that of toothpaste. The paste can be worked with immediately, but curing is recommended.
Lime plaster is also best suited for dry climates. The lime should be sealed with a diluted penetrating sealer–so that it is protected but remains breathable. When working with lime, one should always wear gloves and goggles; it is a caustic material which can burn the skin.
There are many benefits to using Earth and Lime Plasters. –The ingredients are low cost, can be gathered locally, have very low environmental impact, and the final product is esthetically pleasing. These plasters offer a practical, sustainable approach to building.
As a workshop participant, I got to work hands-on with the materials, and as a result, feel that I have a much better understanding of how the building process actually unfolds. I had a lot of fun, and hope to take part in a few more of these workshops over the summer so that I might continue to expand my knowledge on natural building.