Hello! This is a tutorial on how to mix an extremely sticky, high insulation straw clay-plaster using local, natural, and bio-degradable materials. This tutorial will cover the elements necessary to mixing a flexible, durable, and long lasting plaster. This tutorial will also give opportunities for you to work together with your friends, family, or a random anybody who likes getting dirty in sticky mud! In the end you will have created a type of natural adhesive that is sculpt-able and insulating.
Things you'll need:
- 2-3 Friends who like to dance in mud!
- A 2 meter x 2 meter square tarp. A 3mx3m will also do if you would like to mix more with more people!
- 2 shovels (or however many people would like to dig)
- 2 pairs of wet-resistant rubber boots
- 2 x 5 gallon buckets of sand*
- 2 x 5 gallon buckets of clay* (this is the sticky stuff!)
- 2 x 5 gallon buckets of water
- 1 straw bale
- 1 wheelbarrow for transporting the mix
*In most places, you can just substitute sand and clay for abandoned soil. Most soil is very rich in sand and clay along with many other useful sticky elements that help stick the plaster together. So just dig a hole anywhere if you do not have access to sand or clay. Check out the Gardener's World site under References to see how you can find out what is in your soil.
The Natural Building Blog: http://naturalbuildingblog.com/
Straw Plaster and its Uses: http://www.earthsweethome.com/plaster.htm
Earthened Homes from around the Earth: http://naturalhomes.org/
Soil Composition and Formation Information: http://nerrs.noaa.gov/doc/siteprofile/acebasin/html/envicond/soil/slform.htm
The Hungarian Permaculture Forum: http://www.permaforum.hu/permablog
What kind of soil do you have?: http://www.gardenersworld.com/plants/features/structural/find-out-your-soil-type/1118.html
Next step: Preparing the mix...
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Step 1: Lay Out the Tarp Next to the Digging Site
This is Caveman Carl and Buff Brian! They will be guiding you through this Straw Plaster tutorial with much smiles and strength!
Caveman Carl says: It is important to keep all your materials close so that they are easy to access.
Buff Brian says: Set up the tarp next to the digging site. Also prepare the buckets of water, the strawbale, and your pair of water-resistant rubber boots nearby.
In this photo you can see that we have chosen a demolished building site to dig under. This house was sitting on top of a hill of moist soil which is packed full of sand and clay! We had to take out the tile and brick as we dug but it was worth it considering 1) we did not have to get in the car and use polluting energy traveling to the store 2) we did not have to buy sand and clay 3) we were reusing and recycling materials locally 4) we were clearing the construction site for future projects.
Next step: Digging and adding water...
Step 2: Dig, Dig, and More Digging!
In this step, Caveman Carl and Buff Brian have collected 15-20 shovel scoops each of clay, sand, and soil material. That is a total of about 30-40 shovel scoops of material. They have also politely laid the material in the center of the tarp! Good job!
After they have collected all the materials onto the tarp they formed a crater hole in the center of the clay/sand/soil mound with their shovels. Then, as you can see in the second image, they filled the hole with one 5 gallon bucket of water. It should look like a mini Crater lake at the end!
(Image of Crater Lake from Wikipedia: http://upload.wikimedia.org/wikipedia/commons/thumb/b/b5/Crater_lake_oregon.jpg/240px-Crater_lake_oregon.jpg)
Next step: Stomping, Dancing, and adding water...
Step 3: Stomp, Crush, and Dance!
In this step, Carl and Brian are compressing and mixing the wet material with their Rubber Boots. This step is a lot of fun! You can jump, slide, and dance all around in a circle...any movement really helps synergize the materials together with the water to make an evenly consistent material for plastering! Be free and creative! And hold on to each other so no one falls accidentally. Stomp until you have flattened the material into a pancake-like (or crepe-like) shape.
Caveman Carl says: I like to sing a hymn while prancing in circles. Clockwise is best because it follows an energetic mojo that I appreciate.
Buff Brian: I am very serious during this step. Making sure all the large clumps of clay are ground up into oblivion! I also take out any suspected rocks from getting in the mix.
Note: If you feel that the mix is too dry then add water as you go! If you feel that the mix is too wet then add more sand/clay/soil to the mix.
Next step: The burrito technique...
Step 4: Making the Clay Burrito
This step takes a bit of strength! The clay burrito is a technique developed to compress the mixture into a compact form. This compacted form makes it easier to mix with your boots and prevents the mixture from escaping the sides of the tarp.
First, with one person on each side of the tarp, grab onto the corners of the tarp.
Then, lift one side of the tarp and rolling the mixture onto itself. Imagine almost folding one edge of the tarp onto the opposite side.
Then, lift the other side of the tarp, rolling it a second time onto itself. If your mixture is the correct consistency then a burrito-like form will begin to reveal itself.
Remember, The right consistency holds its shape and is neither slimy nor dry. Add material if too slimy and add water if too rocky.
Next step: Adding straw...
Step 5: Stomp, Adding Straw, Stomp
In this step, we stomped the burrito with our Rubber Boots back into a pancake (or crepe-like) shape. Then we added a 1 inch (2-3cm) thick layer of straw covering the entire surface of the mixture. Do this in a way that does not cause chunks of straw in the mixture. You can do this by sprinkling the straw from a distance above the mixture. Here, let Caveman Carl and Buff Brian show you in the third image of this step!
Then stomp the straw into the plaster mixture with your Rubber Boots. You may make another burrito if you wish. It will only help create an even consistency in the end.
Next step: Adding more straw...and making more clay burritos...
Step 6: The Final Preparations
In this step we added another 1 inch (2-3cm) layer of straw completely covering the surface of the mixture. Then we added a half a gallon (2 liters) of water so that the straw can dampen a bit. We found that this allows the straw to soak and fuze much easier with the plaster mixture.
After adding the water we had a great dance on the mixture for about 2 minutes. Then we rolled another burrito and had our final dance on the plaster dance floor!
The end result is a fine and even consistency straw clay plaster!
Next step: Final preparations!
Step 7: The Final Roll and Finish!
In this step we rolled the mixture into a ball by pulling each of the four corners of the tarp one at a time. Then we all carried the clay mixture into the nearby wheelbarrow.
You can see in the images that the consistency of the straw clay plaster has a strong form and slightly heavy in straw. This is the ideal mixture for a well insulated, durable, and long lasting straw plaster! The straw acts as a binder when the plaster dries. Straw essentially meshes the material together like a web. It is important to have many variations of straw lengths to ensure strength throughout the mix. If you can accomplish this then the result is a plaster that will last a lifetime in the walls of your house, around a rocket stove, or as an organic earthen seating area under a roof.
Next step: Closing comments...
Step 8: For Your Benefit
This mixture is not water proof. But if you would like to make this mixture slightly water-resistant you can prepare limestone powder or quicklime to the mixture. However, it is best to use this material where it will not be subject to rain or flooding.
Preparing limestone plaster: http://www.ehow.com/how_4486427_make-lime-building-plaster.html
This plaster was used to cover an Earthship tire foundation for a straw bale house. We raised the foundation, covered the foundation with a tarp sloping outwards, and dug a ditch around the foundation to ensure no water could come in contact with it.
If you would like to witness the construction of this building please visit the Permaforum Blog. The experiment of building this structure will soon be published on the Instrucables site upon its completion and submitted to the next Sustainability Contest. We believe that this structure will benifit many in the future for it is 1) uses natural and local materials 2) does not demand expensive machinery to build 3) can be built under 500 USD (400 EU).
If you are still interested, you can also view the construction/engineering model on my Sustainable Living blog.
Cheers! And I hope that this Instrucable is able to help someone out there! Thank you for your awareness!
Love and Light!