Green Home Building and Sustainable Architecture

Sustainable architecture is an exciting and important field, with many people reviving traditional methods of building and others creating innovations to established practices. Kelly Hart, webmaster of the popular website www.greenhomebuilding.com, posts text and photos featuring what he discovers from around the world.

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Name: Kelly Hart
Location: Crestone, Colorado, United States

Kelly Hart has been involved with green building concepts for much of his life. He has also worked in various fields of communication media, including still photography, cinematography, animation, video production and now website development. Kelly has lived in an earthbag/papercrete home that he built (but is now mostly living in Mexico) and consults about sustainable building design.

December 24, 2004

Amazing Rice Hulls

I have recently become familiar with the use of rice hulls as a material to build with. These unasumming little bits of of debris that are often discarded have found new value as insulation in wood-framed houses and as filler for earthbag projects. They are a durable and renewable material that will not easily burn or decay. They are reported to be about R-3 per inch as insulation, and will not harbor mold or fungus because they don't retain enough moisture to do so. All of this is without any added chemicals...a totally natural product that is often given away. The states where rice mills accumulate hulls include Lousiana, Texas, Arkansa, Missouri, Mississippi, Florida, and California. The hulls only weigh about 9 pounds per cubic foot, so weight is not much of issue in transporting them. They pack into a stable shape when mildly compressed; once they settle into a wall cavity or are packed into an earthbag, they are not shape-shifters.

Don Stephens has been experimenting with rice hulls in bags. He says, "I thought you might find this photo of interest...it's the bag-walled studio I'm mentoring/assisting the owners in building here in Spokane. The bags are just filled with packed, dry rice hulls and they are load-bearing, holding up the insulated bondbeam at the top and the poured-in-ricehull-insulated roof, which will end up planted, over its salvaged-carpet covered Mel-Rol waterproofing. There's been no settlement since construction and it feels SOLID, walking on the roof. The exterior will be stuccoed with slightly-stabilized cob and the interior will be earth plastered. The subfloor is of ricehull-liteclay, for insulation, and will be topped with cob-adobe.... : ) "

11 Comments:

Blogger Shannon said...

This was very helpful in my search for using rice as a material for sustainable housing. If you have more information such as how efficient rice hulls are in comparison to other forms of insulation, i'm very interested. Thanks so much :)

3:16 AM  
Anonymous Anonymous said...

There is more information about various tests that have been performed with rice hulls as insulation at www.esrla.com/shotgun/frame.htm , slides 24-39. Also the issue #47 (Fall 2004) of The Last Straw has a lengthy article.

12:39 PM  
Anonymous Anonymous said...

My company supplied the hulls for Don Stephens project. If any one is interested contact jpereira@rice-hulls.com. You can also check out the following web site about hulls as insulation: http://www.axwoodfarm.com/PAHS/RiceHulls.html

12:57 AM  
Anonymous Anonymous said...

What is the cost of Rice Hulls per ton or pounds----????????? Very interested in knowing these factors before proceeding to utilize.

10:34 AM  
Anonymous Anonymous said...

i'm 15 and i have to do a project on rice hulls and its very hard. this is sort of usefull but its not good enough. i need to know the advantages, disadvantages, radiation, thermal mass, and convection of a rice hull home. can you help me

6:58 PM  
Anonymous Anonymous said...

we are conducting a research bout mixing rice hulls a mixure for making a concrete wall ang study its effects... could someone help us out bout our study... tnx... =)

10:54 PM  
Blogger Terry Ann said...

Does it matter if they are ground or whole?

7:10 AM  
Blogger Kelly Hart said...

I would think that the hulls would provide better insulation if they are left intact rather than ground, because then they will create more effective air pockets. Also, ground or powdered hulls might tend to hold more moisture, which could lead to rotting and less effective insulation.

8:39 AM  
Blogger carmen said...

i'm carmen from the philippines. my project porposal is " minimize cost of hollow blocks by utilizing the rice hulls in toledo city as aggregates.my proposal is related to your study. i would be pleased if you will share topics related to my study. hope to read your reply soon.

10:50 PM  
Blogger Kelly Hart said...

Using rice hulls as an aggregate for lightweight concrete blocks might be quite effective. Such blocks should also be more insulating than conventional ones. I think this idea will require some experiments to see how well it works and to perfect the formulas. Let us know how it works out.

1:10 PM  
Blogger carmen said...

thank you for your comment. i'd be willing to share my studies with you after i will do all the experiments. let's make a greener environment and help save our rivers and mountains.

4:49 AM  

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