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dirt bag structures

 
              
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Location: West Iowa
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I used a sheet of plastic to cover it.  It had a nice test because of all the rain that came.  I came back and had leaked bad.  Since I was working under time contraints and had to change my design from dome to flat roof because it failed, I had to harvest logs real quick and some of them had branch knobs that punctured the plastic lining.  So I threw up some temporary plastic patches and it hardly leaked anymore, but still had some leakage though.  Once I get time, I have to caulk the holes and it should be good for time being. 
 
                                  
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Hi....... my 1st post..... anyone ever think of using a small conveyor to help move the dirt/sand??? 
 
              
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hmm, I'm sure others have thought of more mechanical way to do it, and especially for big projects with little man labor, one may find it worthwhile to look into such things, but I like to keep things simple, and only done a simple project where soil was right at where I was building it.   


And bringing this topic back to the top, In November I put another plastic sheet on the roof, and didn't leak water when it rained, so maybe I'm fixing some of the kinks in this experiment.
couple more pics of it this fall/winter


 
                                    
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my wife and i just finished building our sand bag green house we spent 3 months filling sand bags with moist dirt hand tamping them down with 2 strings of barb wire in between layers I mudded the interior, then stucco the interior. i have mudded the exterior and waiting for the weather to turn to stucco. I will say this it is a lot of work our green house used about 450 to 500 bags for moist dirt. each bag weighs about 70 pounds, our green house is made of used windows and a glass door. it is late January and snowing like crazy, 68 degrees in the green house. we put 6 55 gal black barrels of water against the north wall. i will post pictures of the construction. Also would like to state that we have already built 7 walls, and will be building a office out of sand bags. After that we will build a under ground citrus garden with dwarf citrus trees. I am so excited about this form of building. My father in law turned me on to it. I went to the usual sites on the internet, they said i am doing it. the building was great to build as i lost 20 pounds and my wife dropped 2 dress sizes!!! in these two pics are the bagged green house then the same just with mud on them
greenhouse-005.JPG
[Thumbnail for greenhouse-005.JPG]
green-house-015.JPG
[Thumbnail for green-house-015.JPG]
 
                                    
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here some photos
green-house-016.JPG
[Thumbnail for green-house-016.JPG]
green-house-017.JPG
[Thumbnail for green-house-017.JPG]
 
                                    
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here is more photos
green-house-018.JPG
[Thumbnail for green-house-018.JPG]
green-house-020.JPG
[Thumbnail for green-house-020.JPG]
 
                                    
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ok so i have more photos of the done structure (green house growing patio citrus trees)
green-house-021.JPG
[Thumbnail for green-house-021.JPG]
green-house-022.JPG
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Hi everyone I am new to this forum and have come across earth bag houses and think they are wonderful. Has anyone made one and if so do you think the UK (with it's rainy and cold tendencies) is a suitable place for one to be built. How easy are they to build?
I have seen websites with lovely pictures of them but was hoping for  first hand accounts from people like yourselves.

Many thanks

Just noticed the thread on dirt bag houses sorry for the repeat

 
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beautifulsunset wrote:

Just noticed the thread on dirt bag houses sorry for the repeat



Not a problem!  I used my moderator superpowers to merge your comments into that thread.

 
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Very nice job on both the earthbag shelters.  Very impressive.  Thanks for sharing both  you you.

Jeff
 
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paul wheaton wrote:
I'm guessing that these have really poor insulation. Anybody know?



Dry earth has a good insulative value, I'm sure I don't have to quote your own stuff to you Paul, and the walls are at the very least 10 inches thick, often more depending on the bag size and internal/external plastering.
Obviously moisture barriers are essential for high rainfall climates.

If you are really interested,  "Earthbag Building: The Tools, Tricks and Techniques" is the bible of the technique.

Much respect to LoonyK for getting some work done.
That roof looked a tad flimsyfor the vertical loads though, how's it holding up?
 
Jeffrey Lando
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LoonyK:  Do you have any pics of the inside? 
 
paul wheaton
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I think the r-value for dry dirt is something like 0.3 and fiberglass is something like 3.  So I have to say that dry dirt is not a very good insulator, BUT!  it has the magical property of retaining heat! 

Of course, if you get it super duper thick it's R-value looks pretty good! 

 
paul wheaton
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From gobs of research for my wofati article:  "The R value per inch of a typical straw bale wall is rated between 0.94 and 2.68. The R value per inch of fiberglass batts is 3.1 to 4.3. The R value per inch for dirt is 0.05 when wet and 0.33 when dry. "

 
              
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speedfunk wrote:
LoonyK:  Do you have any pics of the inside?   



I put a pic of it here in the pictorial timeline.  It was fun little project last year, always some new adventure each year...   
http://hybridwillows.weebly.com/earthbag.html

 
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Leah Sattler wrote:
I can see if the door was framed it working. it would be a fun project. what are some ideas to use as the bags? I ...was thinking I can get burlap sacks pretty cheap, or would old feed bags work? I imagine once it is up and has the plaster on it that it wouldn't matter if the original bags deteriorated within the wall ...would it?



Polypro bags are the most commonly used...the type large quantities of rice and what not come in...or, sand bags. I have only used sand bags but burlap supposedly works very well particularly w/ earthen plasters adhering to them. Burlap tends to be more spendy though and most is treated w/ organophosphates to keep bugs away.

On the latter, you are correct....as long as the plaster is on.
 
Rusty Bowman
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Paul,

You're on track with the insulation properties of earth. It has little "r-value". Great mass though (think of it as a battery that stores heat).

Dampened subsoil is the preferred but many materials have been used: sand, coral, gravel, rice hulls, scoria/pumice/cinders and I'm sure more. Kelly Hart built a home using scoria with the theory that the fill would also double as insulation. It's a great idea and one he claims to work well. However, on paper, cinders have an r-value of only .59/inch and  pumice .86/inch. The most commonly used bag is 15" wide so the total r-value is poor...at least on paper. Kelly's walls, however, are covered in papercrete (rather than the standard earthen plaster) which brings the total wall r-value up to around r-25. All in all, it's an intriguing idea but it's met with a fair amount of skepticism.

My field experience with earthbags is limited to a playhouse I built for my daughter (using mostly dampened subsoil). Like most natural building, it requires a lot of physical effort... though I'm guessing less than the tire wall construction. That said, I personally enjoyed working with the earthbag technique and plan to use earthbags on at least some of the interior walls in my new home...mostly for mass.

Ask if you have specific questions and I'll try to answer. Kelly Harts website is a good resource: http://www.greenhomebuilding.com/earthbag.htm

Probably the best source of info are the following two books, particularly the first: Earthbag building: The Tools Tricks & Techniques.....and, Building with Earth: A Guide to Flexible-Form Earthbag Constr.
 
Rob Alexander
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Hi all.
I've been in contact with Donald Kiffmeyer, one of the co-authors of "Earthbag building: The Tools Tricks & Techniques" in the past couple of days about contributing to this forum, and he has said that he would be happy to help us out for a while.
Just bear with me for a couple of days and we can hopefully get some definitive answers to some of the questions that are coming up.
 
                                      
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Hi all you budding dirtbag enthusiasts! Rob asked me to jump in on your earthbag building discussions. I'm happy to answer questions, but don't get me wrong...I love and practice all forms of natural building. It's just that me and my partner Kaki wrote this book called Earthbag Building about 6 years ago, so it seems like we're all about EB's. Oh, but there is so much more to learn isn't there?
I'm not here to convert anyone to a particular type of building method or material. As permies know (and natural builders, too) it's all about climate, environment, location, and availability of materials. Use that which best serves all your purposes.
Ok ok ok...'nuff said...lets get down to the nitty gritty dirt of the matter. Lets dig dirt together!
Doni Kiffmeyer
 
Rob Alexander
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Yay for nice people.
On behalf of all of us I'd like to thank Doni for joining us, and to kick things off, I'd like to re-pose the question from Paul that started this thread off.

paul wheaton wrote:
I'm guessing that these have really poor insulation. Anybody know?



All yours Doni.
 
                                      
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Pretty good guess, Paul. As was stated in the thread of this question, dirt has an R-value of approx. 0.25/inch, so it's not the best of insulators. Keep in mind tho that the R value can be expressed as the coefficient of heat transfer or conductivity - U value (or British Thermal Unit - what we call BTU's). This an inverse proportion of R value; that is U=1/R. So one inch of dirt with an R value of 0.25 has a U value of 4.
As was also stated later in the same thread, This ability to absorb energy and slowly re-radiate it is best utilized in an earthen wall of at least 12 inches thick. This by itself works fine in temperate climates, but where in the world do temperate climates occur? Of course there are some places like that, but most of North America is not exactly temperate. Most places have huge temperature swings seasonally. Even where I live summers are generally over 100 degrees F, while winter temps drop below zero. Certainly burying or berming the structure can create a more temperate climate as the earth's temp is relatively stable below a certain depth - once again depending where you live.
There are no hard and fast rules about how a massive building built with dirt will perform. Just like permaculture, the first rule with building design is observation over a period of time.
But I know, you're all in a hurry and need answers now. If you can't wait to watch and learn, you may want to explore ways to add a degree of insulation to your dirtbag structure and there are as many ways as there are opinions. I've done dirt mixes with 50% pumice stones added to it that gave a degree of insulation, but it decreased it's R value. Remember the inverse proportion? It works both ways.
If you want to have the best of both, R and U values, you can wrap your EB building with an insulative layer of your choice. We explore some options in Earthbag Building, but there are many more that could be (and probably have been) tried. Our only limitation is our imaginations.
This was a long-winded answer to a very short, succinct question. I'll try to be less wordy in the future, but no promises. 
 
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OK what is the best sacks to use for dirt bag const?  Won't the bags fall apart after a while and cause some problems?
 
Rob Alexander
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Woven Polyethylene feed/grain bags are used in general.
People are now buying the bags as tubes on a roll, before they are cut into the small individual bags.
The bags themselves will start to break down if left exposed to sunlight for a long time (months), but once they have been coated with some kind of plaster they last a long time. Polypropylene is one of the more stable plastics, but time will tell just exactly how long they last.
The idea with earthbag building is to properly tamp and "ram" the earth mix inside the the bags so it would in theory be possible to cut away the bags after you're finished if you really wanted to.
In practice, people try to build the structures reasonably quickly and cover the structure with a render to retain the tensile strength of the bags.
Burlap bags are another option, and if handled correctly could potentially last well. Apparently (I haven't been able to confirm it myself) some of the trenches and bunkers built in WW1 using oiled burlap sacks are still standing today, over 90 years later.


 
ronie dee
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How do you tamp dirt in a plastic bag? It kinda seems that the bag wud break.
 
                                      
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First off, bags made of polyethylene are not used. The plastic variety used is a woven polypropylene. This may seem like hair-splitting, but the carbon chain is totally different for each one. The former is not woven; it's the same stuff they offer in grocery stores to put your veggies into. It tears and breaks down quickly and since it isn't woven, it retains moisture, harbors mold, etc. All the things you don't want to happen. Polypropylene is made (primarily) from recycled plastics like soda bottles. The weave allows the dirt fill to completely dry out. Water vapor can easily transpire through it.
Any type of woven material will work for this purpose: polypro, jute (burlap), cotton, etc.
As to ronie's question, the woven bag is very strong; lots of tensile strength. The bag doesn't "break" or split apart if you are using a suitable mix in the bag that is good for ramming (tamping). I once tried to stress out a bag filled with dirt by continuously whaling on it with a 12 lb. sledge hammer. I compressed the fill in the bag to about an inch high. Although the weave was stretched incredibly tight, the bag did not fail. The only time I had bag failure was when I tried to tamp a non-compressible material into the bags - like gravel. The impact btwn my tamper and the angular gravel would cut through the weave.
As for bag longevity - Woven polypro breaks down from UV degradation. Depending on where you live, this can take anywhere from a month to 6 months. The closer to the equator, the quicker they break down. Once protected from this form of light, the bags last indefinitely. This is attested to the fact by the polypro feed/grain bags that have been buried in landfills for up to 30 years (about as long as polypro has been around) are still intact when they have been unearthed. So covering your poly bag work quickly is a good idea. If you can't get around to a plaster, then even protecting them with a tarp is better than nothing.
Burlap (jute) is just the opposite. It will eventually break down when buried due to microbal and bacterial activity. Most of the burlap we get in this country has been treated with a hydrocarbon "dip" that inhibits mold growth and the breakdown below ground. Some people have an extreme allergic reaction to the chemical treatment used on burlap (like my partner Kaki) so I don't use it regularly.
Cotton breaks down from microbal action as well, but with proper care, any of these types of woven bags will work. I use polypro mostly because it is cheaper, relatively stable and some bag manufacturers sell what they call misprinted bags at a reduced cost.
 
Rob Alexander
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Polypropylene, not Polyethylene.
Sorry. It was late when I posted that, brain not working properly.

I was wondering about the intrinsic strength of the bags.
Your "Tamping" with a sledgehammer experiment is pretty impressive.
I guess we just assume that because it's a light, thin plastic that it would fairly weak.
Wow.

 
ronie dee
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So you fill the bag with any dirt or sifted dirt? or mix of dirt?  Then lay bag on ground and tamp it down all the way around for a base Then you lay the the next  bag on top of the lower bag and hammer it? (Offset like block laying.)
 
Rob Alexander
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I just had an epiphany.
Eaves CAUSE splashback.

Gee whiz.

I live in the mountains of Japan, and we have metres of snow in the winter and lotsa rain leading up into summer. The old buildings around here are really nice. Earthen plastered wattle and daub walls, thickly Thatched roofs with deep eave overhangs.

In this environment splashback from the drips from the eaves is a major eroding force on the lower part of the wall, so I was thinking about putting deep eaves on any building I was going to do...but then I epiphed.
Another quietly successful building style around here is elongated arches (with vertical walls up to about head height).
Some people use them to make small garages, and the snow naturally slides off the steep roof, piles up around the building, but gets so thick that it begins to act as insulation during the coldest part of winter.
Everyone I've talked to says that the horizontal forces from the built up snow isn't a problem, and I haven't seen the standard staining on the lowest part of the wall from splashback.

This suggests to me that Domes and Arches could actually be appropriate building shapes in high rainfall areas.
This could be interesting.
 
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Jeremy Bunag wrote:
I'll follow Pixelphoto's lead in thinking out loud:

I guess my question would be how are the junctions sealed?  Maybe I'm thinking too simply, but the implication of "bags" seems to bring to mind "holes." 

Pixelphoto is right in that the monolithic dirt structures are great (like caves), but they're just that:  monolithic.  No crevices/cracks for air to ruin the insulative value.  Much like insulated concrete forms and pouring all the walls to your house in one pour.  No way to get air infiltration.

But I'm imagining something like sandbags (or dirtbags) stacked up, with little fissures for air to infiltrate.  I'm probably simplifying this too much (likely), or I just have no idea how these things work (more likely).

-Jeremy



Better than using bags for dirt construction is using the misprint "tube", you can get a whole role for almost nothing and lay whole courses in one fell swoop.  I built on someone's land a few years ago, three enormous earthbag terraces, twelve courses high and about sixty feet long.  I have never tried to build an actual structure this way, though I love this construction technique.  Read the book. 
 
                                      
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Ronie: Basically, yes. While other earth bldg techniques like cob, adobe, and rammed earth require a fairly specific ratio of clay to sand, the EB method can handle a broader range of dirt ratios due to the encapsulation with the bag itself. However, a rammed earth ratio is the ideal.
Gotta love epiphanies, eh Rob? Keep in mind that the wicking action of moisture is more deleterious than actual splash back. Keeping your plaster far enough off the ground so that water from the ground or melting snow isn't wicking into the whole wall is a good idea. It's the freeze thaw action that does the greatest damage. Even for a dome. Speaking of domes, it's a good idea to have a very rough textured plaster on a dome if you expect a lot of precipitation. A smooth plaster will cause water to sheet down the wall causing rivulets to erode it. A rough textured surface slows the water down and diverts it into many different directions.
Joshua: In regards to the thread; the junctions are sealed by the way the bags are laid and then tamped after a whole row is complete. The ramming action shoulders the bags together and forces them into a very tight seal. I've never had a problem with spaces btwn the bags...and I'm not the kind of person to say "never" or "always." And yes, the tubes are great to work with. It's faster as you don't have to stop, remove the bag from the stand, fold over the top, and lay it down and force it against the previous bag. They are more expensive however as they are not "misprints" as you stated. The tubes are how the fabric comes before the cut, sew and print process, so you would not likely find tubes as misprints. Manufacturers get them in 2000 yard lengths. You can buy them that way or sometimes they have cut off ends of a few hundred feet.
 
Rob Alexander
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Deleterious.
Now THAT's a good word.

I should probably qualify my epiphany a little bit.
Short eaves cause splashback. Really deep, say patio depth, eaves would do a good job, and comprehensive guttering would also ameliorate (like that one?) the detrimental effect of short eaves.
I would definitely use a tall stemwall on a building with no eaves and being a bit fascinated by Lime plasters at the moment, I'm thinking about a  Tadelakt finish on the very bottom of the plaster to increase water resistance.
Minke and Straube have also apparently gotten good results with Siloxane to almost eliminate moisture penetration without dropping vapour permeance in both earth and Lime plasters, which is pretty impressive, but apart from that I know exactly nothing about Siloxane.
Good point about Freeze/Thaw, one winter is enough to turn a cracked road surface in to a pothole minefield where I live.
 
ronie dee
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So one of the links shows them putting barb wire between bags. With tamping and coatings, it seems that the barb wire wouldn't be needed - would it? I don't like the idea of tearing the bags.
 
Rob Alexander
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The barbed wire serves the same function as mortar in a brick wall.
You could build a brick wall without mortar, but it would fall over extremely easily, and that's obviously a very bad idea.
The polyprop bags/tubes are not a single sheet of plastic, they're a woven material, so they already have thousands of holes in them. The barbed wire pokes into the bag like a staple, and the tamped soil helps to grip as well.
People refer to the barbed wire as acting like a "Velcro mortar", so if you reeallly don't want to use the barbed wire, maybe you could develop a velcro coated bag designed specifically for earthbag building...
 
                              
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Hello everyone. Rob wanted me to post on this thread. My better half and I have built an earthbag home. There are lots of pics and a short journal at www.asustainablelife.info. My friend Kinch also started a page: http://www.permies.com/permaculture-forums/3556_0/alternative-building/earthbag-home ; We aren't pros but we tried to use our reason to come up with a good design and implementation.

It is awesome to see Donald Kiffmeyer on here.  His book "Earthbag Building" is an excellent manual and tells you pretty much everything you need to know. Like he said, it's very important to build to suit where you live.  Where we live is wet and we need to take high relative humidity into consideration.  We got some tips on how to do this from the book "Building Green" by Clarke Snell and Tim Callahan (http://www.amazon.com/Building-Green-New-How-Alternative/dp/1600595340/ref=sr_1_2?ie=UTF8&qid=1270837346&sr=8-2-spell).

I've heard some concern over radon. I'm not an expert on the subject but I think that our 6 mil poly in the floor should act as a barrier to it. If this is inaccurate, please let me know! 

To me, earthbags are like cob or adobe but with the added support of the bag, allowing one to build as quickly as possible and not worry about slumping, etc.  Also, if it gets wet, the bags act as mechanical support and hold it in place. 

We went through one of the hardest winters in a long time in this area (The Blue Ridge Mountains) and did pretty well.  Earthbags, in themselves, don't really provide much in the way of insulation.  Their thermal mass tends to stay warm or stay cold, depending what they've been exposed to.  Once you get it heated up well, it tends to stay that way for awhile.  You can also build a rocket mass stove or add some thermal mass to the stove you already have to provide longer heat.  That's what we plan to do.

I know of a guy who build an earthbag place and incorporated some insulation.  http://www.rrylander.com/ - scroll down for pics.  It's an interesting design.  With some changes (recycled styrofoam instead of old clothes, etc) I think it could be really promising.

The polypropylene bags are very tough and we didn't have any break from tamping or be torn by the barbed wire.  Given time, sunlight will break them down but a coat of plaster will avoid this.

We made an easy living roof that seems to be working out great so far.  We already have our first grass going and the straw hasn't been up there very long. 

The biggest problem we've had so far is mold growth caused by condensation on the plastered walls inside.  The walls are painted with lime and we thought that that would discourage any mold growth etc but, apparently, some mold loves the extreme alkilinity of it. We were able to beat it with vinegar mixed with baking soda that we painted over it.  We think it's the salt that it can't grow on. 

Long eaves (ours are 2') and a high stemwall are always a good idea.  Our biggest problem hasn't been moisture from rain or the earth but from condensation during the cold months of winter.

Good luck!
 
Rob Alexander
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Yay for nice people!

Thanks for joining in Morgan.
Congratulations on having taken the plunge and actually built your own place.
Much respect.

Your new digs look snuggly.
Thanks very much for the info on the internal condensation issue.
I hadn't thought about it, but it makes perfect sense.
Internal condensation is a problem in uninsulated concrete buildings, sometimes causing health problems due to mold, not to mention accelerated deterioration of the structure.
So, you heard the man, Insulate.
Your point about the lime plaster growing mold is also very good to know.
A lot of information about lime plasters mention that it has antibacterial properties due to its alkalinity.
Take that with a grain of salt perhaps.

Now for the questions, what is the diameter of the structure, and how do two grownups who love each other (the vast majority of the time), possessions, and the occasional friend fit inside it.
 
                              
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20' internal diameter. For 2 people, it's plenty of room. We've had four people (total) in the house for a few days and, after a while, it feels a bit crowded.  If you can't fit all of your stuff into a 20' by 8' high structure, you've got too much shit! We're going to build a sun room, 10' x 13' with the entire southern wall made of double paned sliding glass doors. On sunny winter days, it'll give us alot of solar gain.  (We'll try to make the floor dark to maximize this effect). An earthship is essentially the same idea - LOTS of thermal mass and southern exposure. 

The amount of condensation we've had doesn't seem to compromise the structure (including the inside plaster) but the mold issues can be potentially serious. 

Whole lotta love, m.
 
                              
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If anyone hasn't looked at this page you should check it out: http://www.greenhomebuilding.com/earthbag.htm
It goes into the possibility of using volcanic rock (scoria) and rice hulls in the bags.
 
                                  
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Just a word about the sliding glass doors.  I believe the majority of them are now low-E glass.  which will help you keep some heat in at night but also keep the heat out during the day...(more what they were designed for)  For solar collection the best might be single payne non-coated.  (best for letting the heat in..... and unfortunately letting the heat back out again)  However the problem may be solved with movable insulated panels to cover the windows at night.
 
Rob Alexander
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Morgan wrote:
If anyone hasn't looked at this page you should check it out: http://www.greenhomebuilding.com/earthbag.htm
It goes into the possibility of using volcanic rock (scoria) and rice hulls in the bags.



If memory serves, that was the first place I came across the idea of Earthbag building.
Living in a rice producing area here in Japan I was particularly interested in the Rice hulls, so I tracked the Owner/Builder of the rice hull studio, Greg Spatz, and he was kind enough to enlighten me with his wisdom and hindsight having built the structure. (Yay for nice people..)

In response to how it's performing..
> The structure is holding up great. It's extremely easy to heat and keep warm. No regrets there whatsoever. I love it.

and the "what would you do differently" question..
> Once the walls were all up, we built a form and poured a concrete bond beam around the top. Then came the roof -- I-beams, sheet rock, tons more rice hulls, and plywood on top.

> Regrets and cautions are as follows: rice hulls are not as stable or solid as straw bales. You cannot use them by themselves for load-bearing structural support. What we would do differently if we had it to do again is this: add some rebar all around the walls for extra rigidity, and add columns for support at either end of the structure. The rice hulls DO compress, but only if you're putting weight on them. Otherwise they seem pretty steady.
In the end we saved our structure by covering it in concrete. Once the concrete was up, the rice hulls were no longer providing any structural support. Essentially we went with what's called a "hard shell"  structure, but only at the last minute, and in order to save the project.

So maybe not ricehulls for those loadbearing structures that most of us are thinking about.
 
                              
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Wow - great update on that project. I've found it very interesting since I first heard about it. If one was going to use hulls, a post and beam structure (perhaps like a strawbale yurt) seems like it would do the trick.

The sliding glass doors we got were from Habitat for Humanity and ran about $25 a set. I don't think either is tinted or glazed but that is an important consideration in terms of solar gain.
 
I knew I would regret that burrito. But this tiny ad has never caused regrets:
A rocket mass heater heats your home with one tenth the wood of a conventional wood stove
http://woodheat.net
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