This is a demonstration of wattle and daub made with bamboo. Wattle and daub is the world’s oldest known building method used all over the world many thousands of years. Here we’re using bamboo. You could use small saplings and branches woven together in the same way. We peeled the bamboo on the surface – the green surface. It would be good to treat the bamboo. There are different ways of doing that. You could see on the Internet. We nailed them together with small nails about 5/8” long. Tack them together. It’s fairly quick and easy. This bamboo has been split with a machete. This sample is about 22” x 36”. You can see how it’s woven. This one goes above, this one goes below. And actually, these should alternate above and below, but because it’s a small sample we just nailed them on top for speed and convenience. We’re using vetiver grass for fiber to help hold the plaster together and reduce cracking. We’re chopping it up into small pieces. If you’re doing a large quantity of this, work on top of a tarp so you capture all the pieces that you’re chopping. Here, I’m chopping directly into the bucket for speed. We’re just making a small sample.
First I showed you the frame – the bamboo frame – that’s the wattle. This is the plaster or daub. We’re demonstrating how to make our plaster. We’re using clay soil. You could also use clay. Dry clay will mix more easily. We’re using some rice hulls to add some fiber and insulation. We’re using the chopped vetiver grass for fiber. We’ve screened out our sand to get rid of these larger pieces. We don’t want those in the plaster. You don’t have to screen the clay or clay soil. We did it so it would mix easier. Add a little water in the mixing container and then keep a bucket of water handy. We don’t want too much water. We want a stiff mix that’s not too wet. To find the best recipe or ratio of ingredients you have to experiment with your soil. What we’re using is roughly a two to one of clay soil to sand. So two clay soil to one sand, and then we’ll add some fiber until it looks good, and just enough water to get the right consistency. We’re going to add the soil a little at a time to let it dissolve in the water. This will save labor mixing. We put it in in layers. That also saves mixing. We’re just making a small sample. If you’re building a house, you’d want to make this in large quantities in a pit or on a tarp. We’ll add the fiber at the end. This looks like a pretty good mix here. Let’s try it out. Take the plaster mix by the handful and work it into the frame (the wattle). You could have another person on the other side doing the same thing, pressing from the other side. You don’t want it too thick. Otherwise it will crack. It looks like a good mix. Now you can smooth it out. Looking good.
This is what it looks like on the back side. If you smooth this out and add some more plaster, it will help it bond to the wattle, make it much stronger. Here’s how we screen the sand using fishing net. This gets rid of the rocks. This is especially important on the finish coat.
This ratio of ingredients worked perfectly and so we’re going to do the same recipe for the next batch and add it to the back. That will help it bond together. The only way to know your (best) recipe is to test it out. The only way to know for sure is to test out your local materials, because soil will vary from location to location. You can pre-soak the clay. That will save some mixing. Add a little water at a time so you don’t add too much. If your sand is wet, then you have to add less water. Of course, you could mechanize the mixing process with a mortar mixer. We’re always trying to demonstrate low cost, low tech methods. A lot of people mix the earthen plaster with their feet.
Now we’re doing the back side. By putting it on both sides it will lock together. This wattle acts as your frame and creates a mechanical bond. So these long fibers are basically wrapping around the wattle to lock everything together. We’re supporting the back side so the first coat doesn’t fall off. And, of course, if you’re actually doing this, this would be a whole wall that’s built solidly. This is just a small sample. This is ideal for interior walls that are thin and don’t take up much space. And, of course, it’s very low cost — virtually free. I’ve been a builder all my life. I have to say this is one of the best, one of the most amazing experiences right here. There’s something very special about this. All of our ancestors all over the world built this way at some point in history. I highly recommend this. This is a good way to build. If you notice, I’m applying it with an upward stroke to resist gravity, to help it stick to the wall better. And again, you could smooth this out, put a finish coat (one or two finish coats) and make it real nice looking.
Hundreds of millions of people lack affordable housing. They’re living in shacks made of cardboard and whatever scraps or pieces of things they can find. Some people may not realize how important this is. This is a very good building method that even if you have no money at all, you could build yourself a pretty nice little home.