What is an Earthen House?
Most of the materials used for building an earth house are unprocessed, natural and local products such as sand, clay, straw and recycled materials. Earth is an abundant resource that can produce beautiful and sustainable homes with a minimal footprint. The following are some examples and explanations of earth homes.
Cob is a mixture of sand, clay, straw and water- wet enough to shape, yet dry enough to build up without forms. It is generally mixed by foot but can also be mixed by machine. Adobe uses the same materials as cob, but is formed into bricks which are dried in the sun and then mortared together. A cob house is essentially monolithic. This with it's curved walls gives them greater strength in earthquakes. Cob invites creativity to be expressed in the process of building your space: be it living space, meditation space, work space, sleeping space or play-space. And who says that walls have to be flat? You can build curves, arches, shelves, benches, niches, fireplaces and ovens. Cob has great thermal mass but a low insulation factor. A fun way of learning is to participate in a workshop; where you build a structure, eat great food while living in community and in the process meet new friends.
Light Straw Clay
Light straw clay comes from an old German technique. Loose straw is mixed with a clay slip and then packed into temporary forms for infill of a wood frame structure. Ideal for earthen plasters; it is light weight, insulative, fire resistant, non load bearing and great for soundproofing.
Straw bales are stacked like blocks to form the walls of a structure (load bearing or infill for post & beam). The bales are then covered with a plaster. Straw bale walls are highly insulative (up to R40) and sound proof. They also work great in combination with cob.
Natural Finishes and Floors
Natural plasters allow the walls to breathe and work great on straw bale or cob. Ingredients traditionally used will include; sand, clay, fibre, manure, lime, glue and mineral pigments. These materials are easy to mix and forgiving to apply. Coloured plasters can be attained by different coloured clay and sand and mineral pigments. Walls can be sealed with casein paints and a glue wash. For earthen floors, linseed oil and bees wax can be used.