UC Davis designed a CoolBot cool room (excellent project for homesteaders!) using rice hull concrete for insulation and a CoolBot controller to keep farm produce fresher. The cool room paid for itself the first year and even helped make a good profit for local farmers. The rice hull concrete was poured into forms to make insulating wall boards. This blog post will briefly summarize the outcome of their project. The full report is available online for free and can be found by searching for the title of the report: Cool room insulation – UC Davis D-Lab
“Announcing the 2nd Rice-Husk-Bag Workshop! This will take place in northern Thailand, November 2015. We will learn how to build walls with bags filled with rice husks (hulls), benches with earthbags, put in doors and windows, cover the walls with a mud, sand and rice husk plaster, and add decorative bottle designs.
Lightweight materials such as rice hulls can speed construction ten-fold. But good design is important! Note how Paul in Thailand (see yesterday’s blog post) added buttresses and steel pipe here and there as problems developed. Basically, he was just “winging it”. Who knows how long the house will last before having mold problems. That’s unfortunate because a similar house built correctly could last many decades.
I haven’t heard from the owner of this rice hull house in a few years. Yesterday I came across some new comments by the builder and thought it would make a good update. A reader had sent a message pointing out how rice hull houses can be built like the strawbale house the other day. (Round, pipe bond beam, etc.) So yeah, here you go. Here’s the step-by-step directions for a rice hull house. Note how lightweight fill materials such as rice hulls require some extra reinforcement from rebar, posts, buttresses, etc. for stability. In contrast, heavy earthbags filled with tamped soil are much more stable. Also note how Paul added wide roof overhangs to better protect the walls.
Richard, a long time reader, is really excited about building with rice hulls. He’s especially interested in using this method after learning from Maggi of Chiang Dao B&B in Thailand that rice hulls are more durable than previously thought. So, not only do rice hulls save lots of time and hard labor, and create a highly insulating walls, they should also last a long time with proper precautions. Richard sent Maggi a list of questions to learn more details.