We’re experimenting with rice hulls and clay to make lightweight building blocks. We’re using 25% rice hulls on our first test block. This is our first test block with a rice hull/clay mixture. This is not the most efficient way to mix it, of course, but we’re just doing small samples. Normally you’d use a pit or a big tarp and mix it with your feet. On my first experiment with rice hull/clay about a year or two ago, I used too much moisture and too many rice hulls. Basically, it was almost all rice hulls with a clay slurry, and it molded. I opened up the bag a month later or so and it was all molded. So I’m using less moisture – just enough to hold it together – and fewer rice hulls. We’re working during the dry season to reduce risk of mold. And in case you’re wondering, humans have been working with fibers and clay, fibers and earth, since the beginning of history, but much of this knowledge has been lost so we’re trying to relearn it. Here’s our first rice hull/clay earthbag. Unfortunately, it’s too wet. I think we have to make another one tomorrow. I think that’s just the way it goes – you just have to keep testing until you find something that works. We just put too much moisture. I made a second earthbag with this rice hull/clay mixture, and you can see it looks a lot drier [note error in video]. This looks pretty good to me. Here are the finished earthbags and block made with rice hull/clay mix. This is to make lightweight walls that also add some insulation.