Earthship Huts - Recycled Modular Buildings
Jonah Reynolds explains how to build sound buildings with healthy energy and water systems mostly using by-products of our global society, such as tyres, cans, glass and plastic bottles, paper and cardboard.
The Hut Earthship is earthquake proof and hurricane resistant. It offers quick and immediate shelter that is strong and easy to build, catching water from the sky and providing clean water for the inhabitant. Earthship Architecture is designed to be modular, to grow, to open like a beautiful flower. The 'Hut' is the smallest Earthship type building that can fully demonstrate the Earthship building concept.
With proper staging, it can be constructed in eight days. The structure begins with a 16ft (4.9m) diameter circular-bearing wall made by ramming discarded automobile tyres with compacted earth. Begin the circle by placing a stake in the middle of where the structure will be. Measure a length of 8ft (2.4m) string, and a little more for the knot. Tie the string to the stake – the string is now your guide to locate the tyres to be rammed with earth to form the walls.
Now you need to place your door frame and a small window frame in the equator facing wall. The first tyre pounded is placed on either side of the door frame. Begin pounding tyres! This bearing wall technique has been approved as an alternative building material all over the USA and in many other countries, including Honduras. It requires no foundation, as the massive wall is already wider than the required foundation.
In some situations the owner/builder may choose to tap into the thermal mass of the earth and sink the structure into the earth about 4ft (1.22m). This is site specific and the water table and stabilization of the earth will dictate if this is possible. If you are not tapping into the thermal mass of the earth and building completely above ground, you will need to wrap the circular tyre wall with straw bales or fibre bale to try and mimic the thermal mass of the earth.
Once the tyre wall is finished, it is packed out. The voids created by the circular tyres next to each other are filled with mud (water, dirt, straw) with cans, bottles, rocks or other object to fill the space. While the tyre wall is being packed out, dirt is bermed against the structure or fibre bales are placed around the tyre wall. Fibre bales must be placed according to typical strawbale architectural guidelines
A concrete bond beam with steel rebar inside is built on the top course of the tyrewall with a small aluminium can wall to form the bond beam. Then two 'bird-cage' domes are place on this bond beam.
The first dome is built of very small wood beams, where wood is available, and in other places where wood is not available, built of steel rebar. The second dome is taller and bigger, made of a steel rebar skeleton. The steel rebar dome skeleton is wired together and covered with a very wide metal lath, like chicken fence mesh. Then, recycled cloth or other similar material found in the local region is dipped in a cement slurry and applied just like paper-mache. The domes are allowed to dry and insulation is stuffed in between. The insulation can be industrial hemp, shredded cloth, shredded paper, spun-glass (batts), etc.
Roofing and rainwater harvesting
Then the domes are plastered a few more times for strength and the outside dome is covered with an elastomeric roofing membrane that allows you to catch potable water. Form a gutter around the edge of the outer dome to catch all the water and direct it to a cistern outside, either buried in the berm, in the ground or above ground. The water is filtered through a simple drain, falling directly into the cistern. Be sure you put in the proper slope for your water to move efficiently into the cistern. At this point you can install the door and window, finish plastering the inside, install a floor and other finishes. Typically lofts are built on the inside, independent of the structure of the building and are about 15ft (4.6m) tall, depending on the shape of your domes. This provides a very sturdy shelter, a rainwater catch and a space for two people. The cistern can be accessed with a scoop or hand pump from inside the space.
This building process lends itself to low-tech applications and can be executed by local people after a practical demonstration and some evening lectures. Five trained people can put up this structure in eight days, providing almost immediate shelter and water. A more substantial structure – cellular growth – can be added as needed
Hut Earthship Workshops are available from Sustainable Solutions, a non-profit organization. Sustainable Solutions comprises designers, builders, educators, regulators, etc. and is working with California building officials and waste management officials to standardize earthship architecture.
Most cans in the UK are still made from steel, and would therefore rust in short order when used for the top bond beam – so we advise using a magnet to test each can.