Feeds:
Posts
Comments

Posts Tagged ‘rice hulls’

Rice hull house wall section (click to enlarge)

Rice hull house wall section (click to enlarge)


Post caps secure the beam to tops of posts

Post caps secure the beam to tops of posts


Yesterday’s blog post on Production Earthbag Building using Rice Hulls introduced one method for building walls with rice hulls. As you can see from the drawing above, the construction process is very straightforward. This method uses a standard post and beam frame with posts set in concrete footers and beams attached to the posts with post caps. The post and beam frame is carefully laid out, plumbed, leveled and squared to achieve good results. The roof is built after the concrete footers have set up. While you’re waiting for the concrete to dry, you can fill the gravel bags or tubes that help protect the rice hulls from moisture damage. Use double bags or tubes for added strength. You can fill the tubes with scoria or pumice in cold climates to create an insulated foundation.

With the roof and gravel bag foundation complete, now you’re ready to fill the rice hull tubes that wrap around the post and beam frame. Tie each tube to each post with baling twine. Fasten tubes out of sight on the backside of the posts to maintain the beauty of the wood frame. 6-penny common nails would work well for this purpose. Drape pre-cut lengths of baling twine every 2 feet or so for later attachment of plaster mesh. You can also use baling twine to tie the tubes together for added rigidity if necessary. Work carefully to keep everything in alignment so there are no bulges in the wall. If you do get some bulges, they can be dealt with by tying opposing dowels, bamboo or saplings together through the wall with twine. (See external pinning.) The tubes will create a solid, superinsulated wall after the plaster is complete.

Image source: Home Hardware
(shop for low cost alternative brands of hardware)

Read Full Post »

A cellulose insulation machine like this one could be used to blow rice hulls into earthbag tubes.

A cellulose insulation machine like this one could be used to blow rice hulls into earthbag tubes.


Cement mixers can greatly reduce labor and speed construction.

Cement mixers can greatly reduce labor and speed construction.


Posthole diggers (augers) can be used to dig holes for posts.

Posthole diggers (augers) can be used to dig holes for posts.


Mike, in Texas, has been asking some interesting questions about wrapping a post and beam frame with tubes of rice hulls. He thinks this is probably the fastest way to build an earthbag house. He may very well be right. Conversations and blog posts like this one are my favorite. Here’s part of my email reply to Mike.

Previously I reported on the rice hull house in Thailand that was a success. The owner has agreed to write a follow-up report soon that we’ll publish here when available. So we know rice hulls will work under certain conditions. The main issue is keeping the hulls dry.

Here are some suggestions for speeding construction. Note how all the machines could be rented so you don’t have to invest in a lot of expensive equipment. You could rent a cellulose machine (blower) and blow rice hulls through a hose into earthbag tubes. (Tubes are faster than bags.) This would take about one day like you said. But you have to figure out how to stabilize the tubes (hold them in a vertical plane and prevent from shifting around). I would put 4×4 posts or round poles about 3′-4′ apart to align with windows, doors and corners. A posthole auger would make quick work of digging holes. Build the roof before proceeding. Factory made trusses are fast and efficient. Now you’re ready to fill the tubes. Put the tubes on the outside of the posts and attach to backside of posts with baling twine. Put baling twine between tubes for later attachment of plaster mesh. Spray the walls with plaster using a mortar sprayer. Use wide roof overhangs and/or wrap-around porches so the rice hulls never get wet and so you can use earth plaster to save money. First 2-3 courses are gravel bags/tubes to prevent moisture problems. In Texas you could make the rubble trench flush with the ground and use just two courses of gravel bags/tubes. Post and beam with factory trusses and engineer’s stamp would enable bank financing, contractor sales, building permits and insurance if necessary.

Earthbag is super simple. But for those just starting out, my earthbag building book and DVD are now available. Everything is explained in great detail.

Below is a work schedule based on a modest sized home with experienced crew and mechanized system (cement mixer, truck to bring the sand and cement right where it’s needed, post hole auger, insulation blower):
Day 1: Dig trench and post holes, rough plumbing, fill trench with gravel, set posts in concrete
Day 2: Set beam, fill 2-3 courses of gravel bags (back truckload of gravel right next to work area)
Day 3: Set trusses, sheath roof, install metal roofing
Day 4:, Fill tubes with rice hulls
Day 5: Minor carpentry (windows, doors, interior walls), run electrical, attach mesh
Day 6, 7, 8: Spray plaster (move mixer and materials right where it’s needed)
Day 9: Earth floor (see blog post on 11 different earth floor methods)
Day 10: Ceiling, finish electrical and plumbing

Image source: Manifold Recording
Image source: Taylor Rental
Image source: Save My Gardening Tips
YouTube: Rice hulls are an excellent building material.

Read Full Post »


If you’ve been watching our videos, you’ve seen us making various earthen blocks. This one here is the best one so far. It has clay and rice hulls. Another very good block was the clay with vetiver grass. So I had the idea to combine the best – the rice hulls and the vetiver. That’s what we’re testing today. This block back here is adobe, just the traditional adobe mix. We’re using this wood form that’s 10”x14”x6” high. That’s a typical size earthen block. You could put these same materials in earthbags, but it’s a lot of extra work. It would only be worthwhile probably if you wanted something special like a lightweight insulated earthbag.

We’re using the same basic ingredients – rice hulls, chopped vetiver for fiber to hold the block together, sifted sand and clay soil. This is not pure clay, this is clay soil. You have to experiment with your own soil and ingredients to get the right mix, but this is what we’ve been using approximately 2:1 — two parts clay soil to one part sand, one part rice hulls, one part vetiver, and enough water to make a stiff mix, but no extra water. Add the clay first – the clay soil actually – with a little bit of water and let it soak. This saves a lot of mixing. Add a little at a time. And again, it would be easier to make this in large quantities in a pit or on a large tarp. We’re just making one small sample here. Add the ingredients in layers to reduce mixing. Add the fiber at the end to make mixing easier.

I like the vetiver grass, because it adds termite resistance and tensile strength. We made a second small batch in order to fill this mold. I think this is going to be our best block so far. We’re combining everything we’ve learned to make a block that’s stronger, lighter, insulating and insect resistant. Another thing we’re doing this time is we’re pouring it in the mold in place. This adobe block we made elsewhere and it cracked as I was carrying it over here to dry. This time we’ll make it right here and we won’t move it around. We should have a stronger block. In about two weeks or so we’re going to test all these blocks that we’ve made and see which ones are the strongest and the best. So stay tuned for our next video.

Naturalhouse’s YouTube channel now with 84 natural building videos.

Read Full Post »

How would you build earthbag walls up to 12 feet above ground on pier footings? A reader asked me this recently. Hmm. Moving tons of earth up that high would be difficult, and that got me thinking of alternatives. One solution I came up with uses an insulation blowing machine and hand-held bag sewing machine to build walls with rice hulls, perlite or similar lightweight insulation.

Insulation Blower

Insulation Blower

Here’s the basic process. One or two workers with large grain scoops shovel rice hulls from a truck directly into the hopper of an insulation blowing machine. A bag filling crew working on a wood framed floor fills and sews bags closed. Other workers stack the bag walls. All walls are tied down with poly strapping and then plastered. Please leave a comment if you have suggestions for improving this idea.

Bag Closing Machine

Bag Closing Machine

Read Full Post »

Looking for the perfect furniture for your new earthbag home?  Everyone’s familiar with bean bag furniture, but most brands use polystyrene fill, a possible carcinogenic.  Consider making your own furniture filled with rice hulls as an all natural fill.

Rice hulls are surprisingly comfortable.  I discovered this by accident about six months ago when I sat down on an earthbag filled with rice hulls.  Rice hulls are strong yet flexible, odor free, flame retarding, rot resistant, and resist settling and compression.  Best of all they’re practically free, since they’re a by-product of harvesting rice.

You will need to make or buy an outer removable cover of canvas, denim, cotton or leather with a zipper.  An inner liner (possibly of earthbags) makes it easy to remove and clean the cover.  One low cost option is to simply cover rice hull-filled earthbags with a blanket or piece of fabric.  This makes moving, adjusting or refilling the bags a breeze.

Shapes include standard bean bag chairs, large chairs for two or more people, ottomans, lounge chairs, floor pillows, kid’s furniture, benches, cushions for other furniture and almost any other shape you can think of.  For example, a bay window loveseat (possibly with storage underneath) could be made very inexpensively.

Here’s a sampling of styles you can find with a Google search: www.awesomebeanbags.com

In addition to the typical uses in dorm rooms, recreation rooms, apartments, etc., bean bag furniture is popular with expectant mothers, the handicapped, and those with injuries or casts.

Read Full Post »