The number one barrier to home ownership is affordability. Many people can’t afford a home made with expensive modern materials, and bank financing. That’s why earthbag building, and natural building in general, is becoming so popular. Why not build it yourself – in stages if you have to – with low cost materials and pay with cash as you go?
Let’s look at the materials required to build a small $300 earthbag dome at about $6/square foot. (Detailed building instructions at Instructables.com)
– Recycled or misprinted bags: Polypropylene bags are widely used for rice, sugar, fertilizer, animal feed and other uses. You can often find used bags at low cost, or you can order misprinted bags at reduced cost from a manufacturer. The standard size for earthbag building is 18”x30”. Mesh bags and burlap bags are others option if you can get them cheaply.
– Subsoil: This is usually available at or near the construction site. Some builders dig a pond and use the excavated soil to build their home. Excavating companies frequently have excess ‘fill dirt’ they’ll gladly sell for cheap, especially if they’re working in the area and you can reduce their trucking costs. Excessively clayey soils can be mixed with sand from a stream or river bed (often available free for the hauling). Overly sandy soils can be mixed with a bit of clayey soil to make more solid earthbags. Another source is sand and gravel producers, who often have ‘reject fines’ or ‘road base’ at low cost.
– Gravel: This is a good fill material for lower courses and can serve as a low-cost ‘gravel bag foundation’. Gravel and/or rubble from old driveways or sidewalks can be broken up and used in a rubble trench under the first course of bags.
– Barbed wire: This adds a lot of tensile strength, which is critical for domes. Most builders use new barbed wire between courses since it’s not a major expense for a small structure. But for those on a tight budget, using recycled barbed wire from old fences is another way to save money. (Make sure it’s in good condition, especially for domes.)
– Tamped earth floors and earth plaster: Experiment with your local soil and find a mix that is suitable. If it shrinks and cracks excessively, add sand. If it doesn’t adhere well, add clay. Adding chopped straw or other fibers will reduce cracking. Earth plaster can become a work of art, with almost any color imaginable. Your floor could be made simply by tamping the mineral subsoil that’s under the dome, although in most climates it’s advantageous to add insulation under the earth floor (such as scoria or pumice) and a moisture barrier.
– Doors, windows and vents: These can all be salvaged. Short pieces of pipe can be buried in the wall for ventilation. Insert some screened pipes low in the wall and some up high on different sides of the building for optimum ventilation. Some builders add operable skylights for greater ventilation and lighting. Arched window and door openings can be formed from barrels, tires or forms built of wood scraps. Consider using old wagon wheels or culvert pipe for window frames.
– Exterior plaster or living roof: Unless you’re living in an extremely dry desert, you’ll need to protect your structure from moisture damage. There are numerous options. Some builders used a soil cement mix to create a reptilian-like scaled surface. Most use lime or cement plaster. Another way is to put 6 mil plastic sheeting and earth over the dome and create a living roof with plants. Living roofs are very beautiful, but they do require a lot of time and effort, and a favorable climate.
Learn more by going to Instructables.com and by searching any of the above keywords in the search engine. We have hundreds of pages of free information that cover virtually every topic.
The blog post would be great, thank you. Do you think his house is cost effective.; the machine to blow the gunite/contracted, the rebar, the machine/contract to blow the close celled foam, are the gunite and the close cell foam expensive?It would be nice to know how much it cost him to build the house, or how much it would cost to build with those materials on a square foot basis.
As far as insulating earthbags in the cold, what would be used; just cob or plaster or do you need more?
Also, I read the article about insulating the earthbags from the outside for cold climates, would spray foam work on that, or the panels like the other guy was mentioning? If not, what type of insulation would you recommend?
Houses like this cost around $10/sq. foot if you’re serious about gathering recycled materials and doing all the work. Most people buy new bags, etc. even though lots of farmers and feed stores have recycled bags for cheap. Don’t hire contractors, they’ll charge a fortune. Figure out a way to do it yourself — do it by hand or rent a machine.
You can insulate with foam board (rigid board insulation) or spray foam. Find out what is most commonly used in your area. Most people use foam board because it creates a flat surface and can be installed rapidly. Attach stucco mesh to the insulation and then add plaster. Only use earth plaster on interior walls or on exterior walls if you have wide roof overhangs.
The ferrocement and foam cost about $10/ sq ft.? Of are you saying the earth bag cost $10./ sqft? Im not sure if this reply ws a reply about Cody Lundins house
No, simple earthbag houses cost $10/sq. ft.
I have been trying to research the cost ferrocement as I am afraid this is the way i will have to do the big vault that my wife fell in love with. I know you said you had read about Cody Lundins house, do you know when you might write that blog? I am really curious as to how much it cost per square foot for him to build it
The blog post is finished and will probably be published in the next 1-3 days. But, like many times, all I do is quote from the original source, which is his website in this case. I don’t have time to dig into the details of every story. If you’re serious about building a house similar to his then consider buying his book, scouring the websites that talk about his house, checking Ecosa Institute he references, etc. to learn as much as you can. I’m highly impressed with the performance of his house and thank you for the tip and nudge to look into it again.
I think the Flying Concrete ferrocement site discusses costs: http://www.flyingconcrete.com/
Ferrocement is affordable (if you do your own work) because only a minimum of materials are used. That’s why they call it ‘thin shell’ construction. It’s clever shell construction versus brute strength approach.
Owen,
Is it possible to do Earthbag for the outter walls and ferrocement for the roof? My wife likes the open floor plans where she can put a loft in it. She wants a large open space for the living room, kitchen, dining room and then wants individual domes for the bedrooms. My concern ism and I guess the question would be how large of a circumference can a eathbag room be and still have an earthbage dome; at what point (room-size) would we “need” to transition to a different method of construction for the dome.
See the Mindfulness Project insulated domes that use ferrocement on the top and earthbags on the bottom: http://earthbagbuilding.wordpress.com/2011/07/27/mindfulness-project-insulated-earthbag-domes/
This method gets difficult when the dome is larger than about 20′. You could go larger if you have sufficient skill and a good design.
Using ferrocement in conjunction with earthbags has enormous potential and I hope more builders consider this option on earthbag domes, roundhouses and vaults. This method is fast, efficient, practical, DIY friendly, easy to insulate and can handle snow loads.
Owen, when you said
” This method gets difficult when the dome is larger than about 20′. You could go larger if you have sufficient skill and a good design.”
is that 20′ at the bottom or top of the Dome?
All dimensions on all plans are interior dimensions at the base.
what is the maximum base dimension I should expect to be able to build from using earthbags, without needing to use the rebar structure for the bags?
Are you talking about domes? Somewhere around 20′ like I said. Experts go a little larger.
Im talking about domes; how big of a diameter can you go with just using earthbags and the plaster on in the inside and outside, nothing else. The design you sent the link to me had derrocement and rebar holding up the earthbag dome didnt it.
I’ve already told you twice. Maximum inside dome diameter is around 20 feet unless you’re experienced.
what part of the west have you yourself lived in?
Colorado mostly, plus a few years in NM.
How do you tell if you will have decent internet? Are there areas that you have heard of that would fit the bill of your earlier thought;
“What I would do is first decide where I’d like to live and where the economy is still fairly good. That would rule out lots of areas quickly. Then start searching within those areas for affordable land, decent Internet, and so on. And yes, there’s lots of land out west with few codes.”
At some point (after you narrow down your search to your top choices) you’ll want to visit and check out the details. Try the Internet in local coffee shops, Internet cafes or libraries. Even little towns are getting wired, so you shouldn’t have to tolerate poor Internet. For me, lousy Internet would rule them out.
There are too many to name. Much of the western US is wild, beautiful, sparsely populated and has few building codes. Colorado has always been way up on the list for me, but that’s just my preference for mountains, trees, streams, hiking and so on. So start with a search for decent economic activity.
If you had to mention 2 towns that would be your first and second pick for paces to check out, which would they be? Since I am looking for an accounting position, we can look all over and would welcome you experience out there. My wife wants to be within 30 min or so of things for the kids to do; they swim competitively, ride horses, and play guitar, snowboard. We started looking at Idaho, Colorado, South Dakota, Wyoming; do you have any thoughts on towns in any of those states?
Well, it’s a personal decision. Some may not like real cold weather. You may need high speed Internet. You may not feel at home in certain places. You really have to visit the places where you might want to live. Top choices in my mind include Colorado (#1), New Mexico, Texas, Montana, Wyoming, eastern Washington, Missouri. This refers to rural areas with few building codes.
having a 13 year old son and a 9 year old daughter, high speed internet is a must lol. We tend to want to stay near some mountains; we all love the snow. We have heard that you eyebrows can freeze off in Montana, but the country does look beautiful. I noticed you mentioned eastern Washington state, have you looked at Idaho at all? I think what would suit my family is a place that gets snow, can see mountains, not too far from skiing, not too far from horses, has a swim team near by, gets snow, able to plant a garden, great people, inexpensive land, able to build with earthbags, ability to be within driving distance of a good accounting job…..not asking too much lol. Where in Colorado would you start you search, do you live in Colorado now?
I’ve never been to Idaho. It is way up there on the list of possibilities. I’m way more familiar with Colorado, where I lived over 20 years. Look on the Earthship Pocket of Freedom map and you’ll see a number of counties up in the mountains with few codes. But it’s tricky because there are few jobs in the area. Actually, most rural areas with few building codes have few jobs.
we dont have to be in the mountains, just be able to see them. I have to be within driving distance to work. If we want to live where there is snow, are there any special considerations for building the earthbag home in that environment?
Most jobs in Colorado are along what’s called the ‘front range’ — on the east side of the Rockies in urban areas. Most of the mountainous areas have small towns with few jobs.
Insulated earthbag houses: http://www.instructables.com/id/How-to-Build-an-Insulated-Earthbag-House/
After reading the article, would it be safe to say that just filling the earthbags with dirt on a site is not the best idea for a cold climate area? What do you think would be the least expensive way to build in cold climates? Have you seen Cody Londins house from Dual Survival? He constructed something in the high desert that was made of rebar and some type of spray material, is this what they mean when they say to use Styrofoam, would this be the best way to go about it?
I read about Cody’s house last year. I didn’t pay much attention since it was ferrocement and foam. Earthbag uses less energy intensive materials. But I went back and read more about his home and now I think it’s worth doing a blog post. His house has very impressive performance and I think reader’s will be interested in some of his ideas.
Earthbags by themselves have almost no insulation. They act as thermal mass. You have to insulate earthbags in cold climates. The simplest way is to add 2″ of insulation on the outside and cover with plaster. That’s the same way many adobe houses are built.
I will graduate with an accounting degree in May of this year, I am willing to drive some distance to make it to work,as long as there is an accounting job there. I was driving an 1.5 ,one way, to get to work up until just after Christmas. Thank you for the link, For the past few years we have been looking out west as an area that we would like to live, seems like from the map that is the area that may be most hospitable for alternative construction. It would be nice if others would help fill in the map for those that can’t/do not want to move to another state. I am going to work on the counties surrounding us here in Virginia and provide the info to them. I am also going to look and see what type of towns are around these free areas. Again, thanks for the link. I would love to buy your book, and I intend to, but, having just been “let go” from my job the day after Christmas, we are in the “chicken with our head cut off mode” in regard to income at this point. Hopefully, your book will still be downloadable when everything shakes out.
What I would do is first decide where I’d like to live and where the economy is still fairly good. That would rule out lots of areas quickly. Then start searching within those areas for affordable land, decent Internet, and so on. And yes, there’s lots of land out west with few codes.
Owen,
Thank you. I read that you were trying to find counties with no/limited building codes, how did that go? I must say that after reading about building code obstacles that others have had, im a bit discouraged that we will find a place to build.
It does add to the challenge, that’s for sure. But there are quite few places with minimal codes if you’re willing to build/live in a rural area. It would help a lot to have an online business or other type of home-based business.
I gave up on the idea of gathering input on the counties after finding the map by the earthship folks “pockets of freedom” http://earthship.com/pockets-of-freedom (This map has some limitations, but it’s a good effort.)
Im sorry I am new to all of this, what does EPDM mean :)?
Google EPDM rubber. It’s a special type of rubber for pond liners and living roofs.
Would you use that setup (living-roof on dome) for a home that would encompass about 1400 sq. ft.? I only ask this because after reading some articles, it seems that the domes may have some water tight integrity concerns. We had thought about having a few (3) smaller domes (150 sq. ft. each) for the bedrooms, and a larger dome or half circle arch for the living room. Should we use a different method (ferrocement) for the domes and the arch/half circle or would the living roof be ok for this.
You can join numerous small domes and add a living roof. I would EPDM rubber membrane over the top, not thin plastic.
How many different sites do you have? Also, I see that the one link you gave me that the house is a living roof, did you do that with the ferrocement setup you were talking about?
I have about 7 sites. Kelly has several. Plus our content is on about 50 sites. Just google ‘geiger’ and whatever sustainable building topic you want. Or use the built-in search engines here and at EarthbagBuilding.com for more targeted searches.
Living roof on dome: read the article. It tells you exactly.
Did you use a metal roof with wood rafters, and was this also included into the $11.50? What phrase would you recommend for me to put in? I have yet to be able to find information (pictures) of how those that have build this way have dealt with the electrical and plumbing, also how they hang pictures, do you know where to find pictures of this aspect of the construction? Do you have pictures of your roof constructions, and an idea of how much that aspect cost?.
Are Domes able to have earth bermed upon them?
Keep reading our blogs and websites. We’ve published hundreds of pages of information because it’s not practical to answer thousands of questions. Almost everything is answered on our sites for free. The roundhouse Instructable shows you almost everything in one article. http://www.instructables.com/id/How-to-Build-an-Earthbag-Roundhouse/
My dome Instructable explains our living roof: http://www.instructables.com/id/How-to-Build-an-Earthbag-Dome/
Owen,
Is the figure of $10.00 per square foot a good estimate for building a earthbag house construction, and does this include any plumbing and electrical? We are hoping to build about a 1400 square foot home, with 3 bedrooms. We have learned that self sufficiency is the best way to live, we are just starting that journey; it is in its infancy. Do you know of any areas (land for sale) that are familiar with this type of construction and less restrictive of them?
Also, are the domed homes with a earth bermed roof cheaper than a metal or wooden roofed structure?
There’s no way to say how much it will cost without doing a cost estimate with accurate costs from your area. Prices vary too much from area to area. $10/sq. ft. is for a developing country. Our roundhouse cost $11.50/sq. ft. with plumbing and electric. http://www.instructables.com/id/How-to-Build-an-Earthbag-Roundhouse/
The least restrictive areas are developing countries. The next best places are in rural areas with few building codes. Search the blog for that phrase and you’ll find a lengthy discussion with lots of suggestions.
Domes may be cheaper, but they have some disadvantages. They’re more exposed to the elements. They’re prone to leakage. They’re prone to overheating in tropical climates. It’s faster (at least for me) to build a roof than to move heavy soil high up in the air to finish off the top of the dome. One good compromise is to use ferrocement on the upper half of the dome and add insulation. But I’m in a rainy climate and so I like a roof with wide overhangs.
Owen,
Thank you for all you do! My family and I thought that due to the economic situation in America that we would never own our own home, we had resolved that rent would be in our future for our entire lives. After a live changing injury, I returned to school to finish a Bachelors in Accounting degree, I will graduate in May. I am not your typical student, I am a 41 yr old father of 2, married for 19 years. We looked at the light at the end of the rainbow; CPA income in a year or so. However, after looking at the price of homes and the financing options out there, we soon realized that any extra money would go out in house payments, and at 41 a 30 year mortgage is not appealing. I have discovered earthbags by accident; trying to find a way to build a less expensive house. I have been reading on this form of building for a week or so now, and the only issues wondered about was could you get a building permit for them and can you get utilities hooked-up to them. After reading i see that this is possible,we are currently looking for an area to build on, we are not opposed to moving, we just need to find the land, and a job of course lol. I just wanted to let you know that you have given our family hope that we can eliminate one of the largest bill that any family will have; house/rent payments. I encourage any family to research this type of construction as a way to decrease debt and add to their savings.
JIm T
As we emphasize throughout this site, build in rural areas with few building codes or the cost could end up being just as much as a conventional house due to all the fees and regulations.