Natural building video script (19m 48s)
Today we’re going to talk about how we can provide housing for people and animals. That’s all we’re going for, how to make homes and structures for all the living species on your site… most particularly the humans.
First, what is a natural building? A natural building is a structure that uses primarily local and natural materials. Some of these materials include:
Earth, which can made into adobe bricks or cob
Stone, or many other natural organic materials.
They can cost a fraction of the price of conventional homes and utilize unwanted or undervalued materials from your community.
A few examples, when I first came to Asia a few years ago, I attended a natural building workshop at the Panya Project in Thailand. Over the course of 2 months, along with about 40 people, we built a community building, a sala, as it was called.
The structure was about 2500 square feet and used natural building techniques like earth bricks, cob, glass bottle bricks and we used second hand doors and window frames. The total cost of the building was about 15,000 usd. This is about 10% of what it would have cost if we were to have built it using more conventional means.
Sort of conversely, I later met a guy named Marco. He started Chiang Mai Life Construction (CLC) company, a high-end bamboo home building company.
“Here, at CLC, we like to combine natural building materials and modern engineering knowledge and create what you might call functional art that is environmentally friendly. And if you look at stability, there are bamboo houses that are several thousand years old. We have no concrete houses that are over 100 years old. With bamboo roofs, if the bamboo is treated correctly, it can last 40-50 years easy.” He said he tried to build a bamboo homes for lower income people but they didn’t want that. They wanted concrete buildings because that’s what rich people live in. He said, “poor people want what rich people have.”
From there, he shifted his focus to build higher end bamboo buildings for wealthier people, and address the shifting demand of society’s trendsetters. He employs about 80 local Thai people and I believe is the only foreigner on his crew.
So whether you build a home yourself or find people like Marco who can do it for you, natural buildings are the future.
Two things that would be good to take away from this chapter:
- You can build your own home, and
- You can build a pretty nice home and it doesn’t have to cost that much.
Common natural building materials
Now we’ll talk a little about common natural building materials. We’ll start with earth. Earthen materials have been used throughout human history for many reasons. It’s cheap and available. In Thailand, a truckload of clay/sand costs about 500 baht, about $20. And every site I’ve ever visited people are a phone call away from finding a truckload of clay or sand. It’s easy to work with, very flexible in design. It’s reusable – When we rebuilt the sala, we actually used the same earthen material to build the new building. Earth also has high thermal mass, which means it acts like a battery. It absorbs heat from the day, releases it at night.
When building with earth there are 3 main components to keep in mind – Clay, sand and fiber. To imagine how these interact with each other, think of a stone wall made of cement, stone and rebar. The stones are the sand, the clay is the cement and the rebar is the fiber.
Sand particles provide the aggregate strength, the bulk material. They don’t expand or contract. Sand prevents the wall from cracking. Then you have clay, clay is the cement, the glue, it holds the wall together. Clay expands and contracts depending on the moisture content. And then fiber, any organic fiber, like rice husks or rice straw, these are two good materials for making bricks or cob… fiber provides tensile strength, which holds the wall together over a distance.
When making mortar mix, sources often say to look for a range, from 15-50% clay, 50-85% sand. The ratio always varies because there is always a different amount of each material. Best thing when making mortar mix, or mud as we call it, is to see what you have and work with it to see what you need to add.
There are a few tests you can do to see what ratio you’re working with. First a sight test. If you chip a chunk of dirt with a hoe or a shovel, if it’s shiny – it has a high clay content. [If it’s dull, the soil has a high sand content.]
Another test is a jar test. For a jar test, fill a jar with soil and water, shake it up, and leave it for 24 hours. When you come back the particles will have separated and you can see the range of materials in your soil.
There’s also a sausage test, where you make a mud sausage about 6 inches long and hold it on one end and kind of wiggle it back and forth. If it doesn’t break at all, too much clay. If it breaks apart near your fingers, too much sand. You want it to break about midway after kind of wiggling it back and forth.
Another test is the ball drop test. To do this, first make a ball about the size of your fist and drop it on the ground. If it holds together completely, it’s has too much clay. If it falls apart completely, it’s has too much sand. You want it to kind of break apart.
Another one is the feel test. You just feel it. You want the mortar to have the consistency of peanut butter. Hold a ball of mud in your hand and tilt your hand to the side. If it sticks to your hand, you have too much clay. And depending on the angle when it falls, you may have too much sand.
There are many tests you can do to test the mud, I think the best test is to make mud and put it on a wall. If it cracks after it dries, you have too much clay. If it doesn’t stick to the wall at all, you have too much sand. After working with mud 2 or 3 times, you’ll really get to know the feel of what good mud is and then whether it has too much clay or sand. You just want to get in range of good mud, that spectrum of good mud.
Okay, here are a few ways to mix mortar. First you can use a tarp, or tarpaulin, just put the materials in the tarp and roll it around from side to side. I always think it looks like a dirt burrito when your done, nice, smooth consistent mud.
Another way is to make a mud pit. Dig a hole about a 30-50cm deep, 2m squared, or whatever size you want. Then throw in your materials and jump in! Making mud in a pit is a great way to reintroduce yourself to the earth and it’s really fun to do with a group of people.
One more way to mix mortar is with a cement mixer. I had a buddy Joe, who made about 1200 bricks at Kailash Akhara using this method. He said, first you want to add the right combination of clay and sand, then you add the fiber. It took a few mixes to get the right combination of clay and sand but when he found a good mix, he could rip out some bricks. 3 people, in one morning, using a cement mixer can make about 90-100 bricks. Where as in a mud pit, 10-15 people can make about 50-60 bricks in a day. And the number of bricks you can make with a tarp varies. I’ve found it’s a lot easier to use a tarp when making smaller amounts of mud.
Okay, so now we have our mortar mix – this mix can be used to make bricks and the mortar. So the same material we use to make the bricks, we use to stack the bricks on a wall.
There are a few ways to make bricks. First is a brick form. It’s just some wood cut to the dimensions of the brick you want to make.
10x20x40cm is a typical size of brick, or half that size, 5 x 10 x 20. The smaller size makes it easier to handle. Place the frame on top of a sheet of plastic and dump in the mud. Using your fingers, make sure you fill all the gaps in the form. Then slowly lift the frame out of the mud. Cover the bricks for the first few days to retain moisture, then let them dry in the sun. After 4 days, flip them. They should dry in about a week.
Another way to make bricks is with a brick press. In Auroville, there are several organizations that make earth bricks. Here, they call them CSEB – compressed, stabilized, earth bricks.
They first sieve the soil to sift out the larger rocks and particles. This is a good idea when making mortar with or without a press. Then they mix a bunch of mud with 1 part cement: 4 parts clay: 8 parts sand. Then they put the mud into the mixer. A team of 4 people can make, I think, about 750 bricks in one a day.
I always thought making earth bricks would be a great business opportunity. People are going to need earth bricks in the future. You only need a good source of dirt, a brick press and a good group of people to run the show. The Auroville Institute has a good manual on how to start a brick-making operation.[ A few tips on laying bricks,
- It’s more important to have the wall be vertically level than horizontally level.
- A well-laid block is impossible to remove with one hand because it sticks well to the mortar.
- Just go. If it’s hard, you’re not doing it right, as Pi Jo from Pun Pun in Thailand says. ]
Cob is a super strong, flexible building material that can be made into any shape. To make cob, just add long fibers, like rice straw or dry grass, instead of short fibers, to your mortar mix.
Make sure you add brown material to the mix. And not green. If it is green, it has nitrogen and will later rot. So you want to build with brown matter, brown has lots of carbon.
When building with cob, you can stack cob by itself and form solid walls. You can also make a wattle, which is a wood or bamboo frame, with cob wrapped around the wattle. When building with cob, it’s good to make dreadlocks, just thick masses of straw that look like dreadlocks. You want to make a lot of knots and twists around itself or whatever frame your building in. This makes for a stronger bond when the mud dries.
Chip and slip / straw clay
Another type of cob building technique is called chip and slip, or straw-clay building. To build a straw clay wall, you first make a frame out of wood, 20cm thick. Then stuff the middle with clayey straw. This means you want just a little amount of wet clay, no chunks.
I had a chance to visit a community in Alaska, called Ionia – www.ionia.org. They claimed to be building the largest straw clay building in the world. They are a group of families from the East and West coast of the US. They headed north about 40 years ago and have since established a nice, quiet community in a remote part of Alaska.
Okay, now moving on to plastering. Plaster protects a wall from elements and can add a classy touch to a wall. Two kinds of plaster we’ll talk about here – a rough coat and a final coat. The rough coat is the same as mortar mix, just apply it straight to the wall. You can use a trowel or use your hands. I think using your hands is effective. With the rough coat, we’re just looking to cover up the weak spots, and try to make the wall flat. We can cover up mistakes we make from the first wall.
Then for the final coat, there are a few things you can do. You can chip straw, using a wood chipper, into fine strands, then you can ferment the straw in water for a few days, or until it starts to smell. When it starts to smell, it is decomposing and becoming gluey. This gluey part makes it stick more easily to the wall and adds a nice gluey finish.
You can also add cow manure to your plaster mix: 4 parts sand: 1 part clay: 5 parts cow manure. This helps harden the wall and create water resistance.
Crushed glass bottles
Another trick is to fill a cement mixer with glass bottles and fist-sized rocks. In a few minutes, the mixer will crush the bottles and turn them almost back into sand. Then you add this to your final plaster. The wall shines. [Note: When I tried this before, it almost ruined the motor. So use caution when putting rocks into a cement mixer.]
Natural paints are another way to add color to a wall. Earth already has a color to it. So when your thinking about the color of a wall, first see what the mud looks like when it dries. You can also make natural paint by first mixing 1 cup tapioca, or regular flour works as well with 1 cup cold water. Then add 4 cups of boiling water. This makes white paint. To add colors, turmeric makes yellow, rust particles make brown, beets make a deep red and then you have other natural dyes. You can also add sand to create more texture to the paint.
Natural sealants are a good way to protect your wall from water. Linseed oil works great. Also called flax seed, this stuff turns a gritty, dirt plaster into a smooth, polished surface. Diluting linseed oil with turpentine, around a 1:1 ratio, enables you to get some more distance out of the solution. Beeswax, waterglass are other natural sealants, if you can find them.
Building with glass bottle bricks
Bottle bricks are another fun and creative way to build. To make bottle bricks you need a diamond cutter and a small wood block. First you score the bottle just before it bends to the mouth of the bottle. So you score the bottle, fill it with water to the score line, wrap it with thread soaked in gasoline, burn it and right before it goes out, dunk the whole bottle in a bucket of water. The glass will split right on the line. Then tape the open end to another broken bottle and you have a bottle brick.
Earthbags are a cheap, quick and easy way to build fortress-like structures. Sometimes called super adobe, building with earthbags require very little technical knowledge and have lots of design flexibility. All you need are some rice sacks. The sand/clay ratio is unimportant when working with earthbags. 20kg is a good size, anything larger is too wide… you also need barbed wire, a tamper and of course a good pile of dirt. They also sell long tubes of the rice sack material, but rice sacks alone work fine.
When you build with earthbags, fill a few sacks with dirt and place them where you want your wall to go. Then tamp the bags with the tamper. Then stick 2 lines of barbed wire on top of the bags before the next row. This holds each layer together. You can build a wall in a few hours.
Another good method of natural building is rammed earth. Rammed earth is compressed earth walls. They are waterproof once constructed, they need no plaster. Rammed earth walls look like layered sandstone, like an archeological dig. These two guys, Nick and Peter, were building a rammed earth house at Kailash Akhara.
They provided a few tips: they said to make sure to invest in steel panels. They were using plywood and the panels were worn after a few uses. You spend most of your time constructing and deconstructing the form wall. So the better your wall system is, the faster you can build.
To build with rammed earth you first make the foundation and divide the wall into sections. When you make the foundation, be sure to have rebar sticking up in the middle of each wall section to secure it to the ground. Then construct the form.
The mortar mix again will vary. One ratio they used at Kailash Akhara was 4 cement: 5 gravel: 6 sand: 13 sifted clay. Again, this is going to vary. It took Nick and Peter a few wall sections to find the right ratio. They also suggested to make the walls 20cm thick, any wider is too much work.
Bamboo is a grass and it is one of the fastest growing plants in the world. Some species of bamboo can grow up to 1 meter in a day. It is also a very flexible building material. One of the challenges is curing the bamboo. Cutting it at the end of the dry season is when bamboo will have the least amount of sugar. You can also soak bamboo in borax, a kind of not-too-harmful chemical solution. Or soak them in water.
At the Art of Living permaculture site in Bangalore, India, we built a bamboo / cob classroom. We harvested the bamboo from another part of the ashram, actually next to the first temple built by the Art of Living. It was a very sacred place. We cut a few hundred pieces and let them dry in the sun for about a week. We built a circle frame with the bamboo. Since the pieces were still green, we could bend them. This helped with the dome roof we built.
Strawbale is cheap and easy way to build structures in temperate climates. Strawbales have 2-3 times the R-value of commercial fiberglass insulation. R-value is the capacity of a material to resist heat flow. Where thermal mass is like a battery, insulation is like a mirror. Strawbale resists temperature changes. This makes them great in cold climates.
Unsustainable building materials
Just briefly about unsustainable building materials. These are materials that require a lot of energy to make and create a lot of pollution in doing so… the main examples of unsustainable building materials are steel, concrete and synthetic paints. I’ve found there is this ongoing debate among people who are into this lifestyle already. Do you build homes that will last or do you build homes that are natural. I think it’s best to use your own judgement. There is an unending ethical line and we’re not really sure, you know, just do whatever you think will last the longest and whatever you are interested in at the time.
Speaking of unsustainable building techniques, here’s a guy who built an island from 150,000 plastic bottles. Here are some video clips from online about Richard Sowa and his island of bottles. “It’s made from plastic bottles, all of the bottles have tops so each have some air inside it and that floats. All of those are put in fruit sacks which are available worldwide, all of these things are available worldwide. So it just becomes like a piece of sand, you can see the movement there, look. This is a concept that makes land, not only makes land but makes oxygen. Space for people to live because we’ve got a population explosion all over the whole planet… but the solution is all that trash that we don’t really know what to do with, can actually solve the problems of the world.
It’s really amazing the potential we can do with building when we get into the mindset of seeing and trying out what is possible.
The last thing I’ll talk about is the Matrimandir. The Matrimandir is a large gold ball located in the middle of Auroville. Inside the building are numerous meditation rooms, the sound of running water and in the center, another meditation room, with light coming down from the ceiling, piercing this large crystal ball. It took 40 years to build the structure. They used only volunteer labor. It is magnificent. The Matrimandir truly demonstrates the capacity of human ingenuity.
The more I learn about natural building and well, life in general, the more I wonder, what structures are we going to leave behind? We still look back in our history and wonder how they built the pyramids, or built stonehenge, or carved faces on the rocks on Easter Island…
Why stop at the Matrimandir? Let’s do it again. And again. And again. And again. And again. Until the whole planet is filled with spectacular human creations you can see from the moon. So you know, let’s make this place livable, make it nice, let’s make this place our home. This is where we live.
Let’s also make this place look as magnificent as humanly possible so when we do go to space… we’ll be leaving to explore space, not escape earth. This is the job. This is the work. This is what we’re supposed to do.
Okay, so to briefly recap this chapter…
- You can build anything with natural materials.
- There are a variety of natural materials you can use
- Let’s still use cement and steel and oil… they’re exceptional unique and awesome products. We just need to use them in moderation.
- There are no limits to what we can create.
On your designs, think about what structures you want to build. What materials you have available? What designs would you like to create? Okay, this concludes part I of the natural building chapter. Thank you for your time