Building in Light Earth

There are more earth buildings in the world than concrete. And the world is fast running out of the resources for concrete. So it takes humility, courage and wisdom to adopt one of the oldest building materials on earth. Building in earth is our brave new future.

“The main earth building techniques include: Mudbrick (Mud Brick, Adobe),  Rammed Earth (Pise),  CobPressed Earth Brick (CEB-Compressed Earth Brick /Block, Cinva Ram),   Poured Earth,    Super Adobe (Earth Bag),  Wattle & Daub,   Light Earth (Light Straw Clay, Slip Straw),    Earth Renders (Earthen Render), Earth Plasters (Earthen Plaster).
Earth Builders Association Australia

This video demonstrates Will and Kenny’s newly developed machinery for making light earth. It is lightweight, affordable, insulating and can work with nearly all types of clay subsoils.

Four Foundations for Better Future

Climate action requires us to stop polluting, think and learn from the past, plan and then make real changes. Here are the four ways our buildings can make a better future.

1. Buildings can be designed or redesigned to be climate responsive
2. Materials can have low negative impact on the environment and some can even absorb greenhouse gases
3. We can own up to the failings of the cities and suburban mega-mansions of the western world
4. We can recognise the beauty and function of earth buildings and help make them fashionable so the 2/3rds world continues the earth building practice with pride

Stunning Musgum huts in the shape of a shell in Far North province, Cameroon
CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=76353

Workshop with Will and Kenny

Will Eastlake and Kenny LeMire run MUDTECH and Integrated Biotecture Design. They are environmentally conscious architects and earth builders. Here they show us how to use clay coated straw to build a light earth wall. In addition to the light earth wall, they also supplied the clay coated straw for an experimental composite wall designed by Ray Trappel which had the addition cob slapped onto the sides of the framework.

Will and Kenny usually make a lot of compressed mud bricks. But they’re also building designers. They work a lot with owner builders and run workshops. The workshop featured in this film is light earth wall technique. These workshops have been great bring people together and build things relatively quickly.

Tamping the light earth into the formwork

Light Earth – Adaptable

Will says “I like that it pretty much can use any clays. Even high reactive clays are even better cause it glues it better. So, we can get site soil, and mix it up into a clay slip.. You can get bags of clay from the hardware store but you can also dig down and try and find clay. Usually we would use the clay on site. We dig down to a clay seam.

Then we get the the pure clay and soak it in tubs for weeks leading up to the day of the build. And then you have someone breaking up that clay which goes into the mixer. Then that disperses. And it can be difficult to deal with. You aim to minimize the thermal mass components – like the sands and silt. We want to get just a thin bit of clay slip on the straw. There is no stabilizer cement or lime to worry about. We check the straw has a good coverage of slip on it. Then, we take it to the wall and do the tamping process.

How high can build in light earth?

During this workshop someone asked “How high can you build the wall?” A good timber frame with studs at 600mm makes it more secure. The span in the demonstration framework was much longer than Kenny and Will normally use. Will said “we’ve done double story walls quite easily.” Another questions was “Why do you have to Tamp? because we need to make the wall materials the right density. So we pack more into the edges and none (almost) in the middle.

Finished demonstration light earth wall – Photo by Will Eastlake

Why build?

Learning to build with mud empowers people. Better still, light earth is quick, light and cheap. The wall good insulation properties. And the process is not back breaking! Children were able to get involved. You can build in light earth with machinery. Will and Kenny developed the machinery to speed up the process for commercial applications. But it is easy to convert an old wall with light straw.

Mud Stomping preparing clay for building in cob takes a bit more effort

Best of all, all the ingredients in the wall are reusable. Will explains that because the clay is “unstabilized, you can reuse and capture everything”. This fits well with Permaculture design for reuse, cycling nutrients and minimising inputs.

You can learn more about Permaculture Design with us. And you can learn more about natural building at Earth Builders Association of Australia.