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Picture of How to Build an Insulated Earthbag House

For those new to earthbag building, please read my Step-by-Step Earthbag Building Instructable . Also, my new Earthbag Building Guide and Earthbag Building DVD are now available.

Energy performance on most buildings can be improved with insulation, including those made of earth such as adobe and earthbag structures. Although most earthen structures are located in hot, dry climates, there is increasing demand for low-cost, eco-friendly earth building techniques in cold climates. This article explores four innovative methods for insulating earthbag buildings, which extends their building range to cold regions.

Most earthbag buildings use polypropylene grain bags or mesh bags filled with soil. Bags or tubes can be used. We demonstrate bags, because they’re often available recycled for very low cost. The bags or tubes are filled in level courses and then tamped solid. There are typically two strands of barbed wire between courses to bond the bags to each other and add tensile strength. The building process for insulated earthbag houses is nearly the same, although the materials would weigh significantly less and speed construction considerably.

Unlike other earth building methods, earthbag building has the unique advantage of providing either thermal mass or insulation, and therefore can be adapted for cold climates with an insulated fill material. Scoria, pumice, perlite, vermiculite or rice hulls are all suitable insulating materials. These materials are natural, lightweight, easy to work with and non-toxic. Most (all but rice hulls) will not burn or rot and do not attract insects or vermin. In addition, all but rice hulls are not adversely affected by moisture and can be used as part of earth-bermed or earth-sheltered structures. Recycled polystyrene (Styrofoam) is another good possibility. Another possibility is adding foam board or foam insulation on the exterior of earthbag walls, as explained in the 4th option.

The table below compares the approximate R-values of five low cost insulating materials that could be used in earthbags. (The first column in the table is the insulative value per inch; the second column shows the R-value for a typical 15" thick earthbag wall.)
Material -- R-value/inch -- R-value/15"
Rice hulls -- R-3 -- R-45
Perlite -- R-2.7 -- R-40
Vermiculite -- R-2.13 -- R-32 to 36
Extruded polystyrene -- R-3.6 to R-4.7 -- R-54 to R-70
Molded polystyrene (low density) -- R-3.85 – R-58
(Source: Wikipedia Encyclopedia.) http://en.wikipedia.org/wiki/R-value_(insulation)

Tools and supplies:
Shovel, bucket, garden hose, tamper, slider, gravel, soil and/or insulation, earthbags (poly sand bags), barbed wire, wire cutters, level

The following pages discuss four low cost methods of building insulated earthbag houses.

For more information, my You Tube Channel has dozens of short videos showing every step of earthbag building.  And our Earthbag Building Blog , the number one blog on the subject, covers every aspect of building with bags in detail.


 
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BillN421 days ago

Owen -

I see on one of your follow up comments that you live in a tropical climate. I am currently investigating a dome-shaped earthbag/super adobe to be built in hot & humid Costa Rica.

I see that you used 18" tamped earth. I am wondering how cool it stays inside your home and what type of roof you're under?

Owen Geiger (author)  BillN421 days ago
Read the How to Build an Earthbag Roundhouse Instructable. That roundhouse stays the same temperature inside year-round with no insulation here in Thailand.

Search our Natural Building Blog for two articles about Passive Solar Cooling. Choose 10-15 strategies and you won't need AC.

Domes evolved in deserts and so you will have ongoing maintenance trying to prevent roof leaks. All plaster cracks and the water will leak in. Best to build a roofed dome if you want a dome home. See our gallery section at Earthbag Building.com for photos of roofed domes.

Domes are also a little tricky to build and the fill material needs to be stabilized. The easiest, fastest way to build is earthbag roundhouses.
Thanks Owen!

I am considering a group of round houses in Jaco Costa Rica which is pretty hot - probably not unlike where you are in Thailand.

I have been looking at doing some earth tubes and a solar chimney to pull cool air through tubes that are buried several meters below ground.

Have you ever tried this? My biggest concern is the issue of potential mold because the climate is humid as well as hot.

ROOFING Question to go along with cooling:

I know you use a thatch roof on your round house. Do you ever have trouble with wind? Costa Rica has two very, very windy months with gusts up to 100kph.
SarahS151 month ago

One thing I'm mildly confused about...Can I (in the cold and wet NE US) use perlite to fill my earthbags entirely, or would I use them as an outside insulating wall to an earthbag wall made of...well, earth? Perlite's sort of crunchy and I don't see it being able to support itself being made into a building. It's cost effective and locally produced around here with all the natural vermiculite that I could also use, trusting its less crunchy nature. Which would you suggest that I use in Pennsylvania and how would I use it (directly in the bags or a course concurrently running along side the earth-filled earth bags)?

Owen Geiger (author)  SarahS151 month ago

Building with perlite, vermiculite and, to a certain degree, rice hulls is still experimental so it's best to build small, simple structures until you develop the necessary skills. See this article called Earthbag Scoria Casita for details on how to stabilize bag walls filled with loose insulation: Watch all the videos carefully.

http://www.naturalbuildingblog.com/earthbag-scoria-casita/

I'm willing to try perlite as a small shed project. If it's successful, we'll definitely let you know. I would love to try scoria, but there's just no suppliers up here, whereas there's a perlite plant in Bethlehem, not even an hour away. Vermiculite would be more promising if it didn't expand when wet, and PA gets very wet, except when it doesn't. I'll make plans to make a shed, but it'll have to wait a year. I'm going to be a senior and my studies are about to get more insane. Thank you again for your input.
Trakway2 months ago

To build an insulated Earth-bag House, we can take a suggestion and tips from lesson. Your article is good for this. Thanks.

http://2jtrakway.com.au/construction/

BenniGholami5 months ago

Haha given that the house provides insulation, I really don't think houses for sale with these features will do very well in Phuket where it's swelteringly hot almost all year around :)

Owen Geiger (author)  BenniGholami5 months ago
This article is for cold climates. However, insulation works in hot and cold climates. Our earthbag roundhouse stays the same cool, comfortable temperature 365 days/year in our tropical climate.Think how much money you could save on AC.By the way, there's no insulation in our roundhouse. The tamped earth creates thick 18" thick high mass walls that keep it cool. So both ways will work. We use tamped earth because that's what's low cost and readily available.
vonkking6 months ago

Owen, I am not physically able to build this myself. If you'd come to ND to help, I'd feed you...or, do you have any other ideas? Thanks, Von

Owen Geiger (author)  vonkking6 months ago

I can't come personally, but there are always options. Create a free blog. Turn the project into an educational/training event for sustainable building. Post messages on various websites such as our free Bulletin Board at Natural Building Blog. Talk to local youth groups, etc. The key is for you to become informed and be the leader to make it happen. Same with everything in life.

I'm checking this out for the first time too - initial questions are: Do you see this construction used in an urban setting? I'm questioning if there would be zoning issues which I'd need to research. I want to buy a lot ( small parcel of city land) and build something small, green, and alternative to live in - I'd like to try to to get funding (maybe a non-pofit, or green grant) and make it a research project... but still in the infancy of this idea. I see it as an art and architectural statement with a hint of sustainable housing (small footprint, new/alternative technologies, low waste, and cost to build). Thanks for any hints or ideas relating to anything I've said -just feeling this out. Please note I am connected to art and design but do not have a formal architecture or construction background. I don't have a lot of money either. Haha - I just believe you need to dream and sometimes just do things you know nothing about to make progress.

Owen Geiger (author)  lisa.dumitrescu6 months ago

This is something I talk a lot about on our Natural Building blog because it's the #1 topic. Millions or billions of people are in the same situation. The bottom line is building codes were written by the giant construction industries: brick, steel, concrete, timber and insurance industries to favor themselves. They left a loophole in the code for alternative materials,so in theory you could build this way in cities but the reality is it will cost you 10 times as much. You'll need engineering approval and loads of money to throw at the building department and for extra materials. Up to you. I recommend building in rural areas with few or no codes. Our most popular blog post is titled Counties with Few or No Building Codes:

http://www.naturalbuildingblog.com/counties-with-few-or-no-building-codes/

kathm18 months ago

I have checked out both of the links you provided and both were extremely helpful too. I've been on the lookout for easier ways to building earthbag houses. I think your suggestions will work perfectly. They seem a lot easier compared to the ones I've read about before.

______________

Tiptop Insulation

In Home Insulation Specialists Adelaide

a033264951 year ago
Can you elaborate on the choice to put the thermal mass on the inside v the outside of the insulation? I'm operating in the Sacramento climate (both a heating and cooling climate, characterized by large daily swings in temperature).

http://www.weather.com/weather/wxclimatology/monthly/graph/USCA0967

Does it make sense to think about thermal mass/insulation/thermal mass assemblies, or is that unnecessarily complicated?
Owen Geiger (author)  a033264959 months ago

Add rigid foam insulation on the exterior and then cover with plaster.

Hi my name is Louise, I live in Thailand on an island called Koh Samui. I have already designed and built my first home here and am now considering building an earth bag built house and need some advice as it is hot and humid here as to what I can fill it with and is it a good idea in this humidity ?
Owen Geiger (author)  Louise Innocent9 months ago

Common subsoil is most commonly used. The clay helps bind the sand into solid walls. Island are typically all sand. Mix in some clay if you can find it. Otherwise you'll probably have to add some cement or lime as a stabilizer.

Corynder2 years ago
Hello :) My friend is looking into different possibilites regarding building on her land. The problem is that her land is very sandy and so things I have some experience in (such as mudbrick) aren't going to work. But I think that could also be a great asset as well if we figured out how to use it right.

How is sand for a filler? As insulation? I'm guessing it's not very flammable, which is great, but would you recommend it or mixing it with something?
Owen Geiger (author)  Corynder2 years ago
Mix some clay with the sand until your test bags dry hard and strong. Or you could add a little cement or lime to the sand as stabilizer. You could also search our Natural Building Blog for the building method developed by Eternally Solar. Their specially designed tubes (which you could make) are designed for sand. You can use their system free of charge if it's non-commercial. All details are provided if you search the site.
We've purchased your books and are about ready to start buying what we need to get started. I am finding a lot of contractors advertise their leftover building materials on Craigslist so we are picking up things now for either very little or for free like windows, doors, boards, etc. Our next purchase will be the bags and barbed wire. We want everything we need while we can still buy things. We just purchased a Kimberly Stove and after the earthbags we will buy a Sun-Mar Composting toilet. We should be really close then to having what we need... or at least I hope so. I absolutely love earthbag houses but especially like the earth bermed one. We want an earth bermed house with a green house on the front side. Thank you so much for getting this information out!!! We are buying land in a county that does not require building codes. How are others doing this in counties that require a permit for everything? Are they having any problems getting permits for this type of building? Thank You.
It sounds like you're making all the right moves as far as planning ahead, buying used materials, etc. Choosing a county with no building codes can save you thousands or even tens of thousands of dollars. For instance, most areas require certain room sizes and overall minimum house size with covenants, etc. So instead of building a 1,000 sq. ft. box for instance, you can build just what you need and want. You can always add on later, so we always recommend starting out small and simple. Also, codes require lots of extra steel and concrete. In your case you can build an earthbag foundation instead of concrete. That one step alone can save you $2,000 or more depending on where you live and the size of your home.

Be sure to read my instructable on How to Build Dirt Cheap Houses.
http://www.instructables.com/id/How-to-Build-Dirt-Cheap-Houses/
It describes how you can save thousands of dollars on every step of construction. But like you know, this is only possible if you live where there aren't any codes. Plus, you'll be more free to grow your own food, raise chickens, dig your own well for self sufficiency, etc.

And yes, building in building code areas is much more difficult as you can imagine. It can be done, but it's a lot more time, money and effort.
candyland223 years ago
I have just stumbled upon earthbag homes about 2 hours ago and have changed my mind from a log home kit to this! I live in upstate Ny and recieved some land from my mother in law in the adirondacks! Would these homes be ideal for the weather conditions? If we had a outdoor wood furnace could we run the heating pipe through the wall without damaging anything? My husband and I are not very construction savvy! Also how do you run electric? Thank you in advance! :)
Owen Geiger (author)  candyland223 years ago
You have to weigh all the advantages and disadvantages and decide what's best for you. No one building system is perfect for all situations. For instance, maybe you have an abundance of wood that could be used for cordwood building. Or maybe you have excellent stone for building. Or low cost straw bales from a local farmer...

Everything you need is free on our various websites -- YouTube, EarthbagBuilding.com, Instructables, Earthbag Building Blog. Just google it. Every topic such as how to install electrical is shown in detail.

No problem running pipes through the wall for a wood furnace.

If you do go with earthbags in NY or other cold climate, you'll need to add insulation. Here's one of many free articles that will help you: http://www.instructables.com/id/How-to-Build-an-Insulated-Earthbag-House/
Now if we decided to expand our earthbag home, how could that happen? Is it possible or would it risk the strength of the structure to cut a doorway out into another room? I also was playing with the idea of a mix of earthbag and cordwood for a more dynamic look.
Owen Geiger (author)  candyland223 years ago
It's best to plan ahead because it's difficult cutting out doorways later. One way is to frame a window opening like a door so it's easy to convert to a door later. (Bags sit inside the buck under the window.) Cut the plaster next to the buck, knock out the bags and there's your framed door opening.

Our blog talks about how to use buttresses to join new earthbag walls in the future. This and all topics are covered in detail in 1,100+ blog posts. Use the built-in search engine or buy my Earthbag Building Guide book that summarizes all the most important info. http://www.earthbagbuilding.com/articles/ebbuildingguide.htm

Joining cordwood and earthbags is easy if you make the cordwood the same length as earthbags (about 18").
Thank you for all your help so far! Im purchasing your book as soon as the land is in my name! I was GIVEN 5 beautiful acres (thank you mother in law) so this really is going to be quite the low cost home!
CarolAnn5253 years ago
Hello Owen,
My husband and I just got your book and are very excited about building.

We are planning to build in northern Minnesota and are wondering if anyone knows of an earth bag home in this state. I know of a straw bale home but not an earth bag. Would the building codes for earth bag be the same as straw bale, or comparable?
Also we plan on a 50/50 mix of volcanic rock to native earth. Do you think that would be a good insulation? Should we insulate the exterior as well? We also want to build a basement either under half or the whole structure, is that a good idea? Can it be done?


Thank you for your help with our questions. G-d bless you for your knowledge and consideration, CarolAnn
Owen Geiger (author)  CarolAnn5253 years ago
I don't know of any earthbag houses in Minnesota, but then again most people don't publicize their projects. Earthbag and strawbale both fall under the Alternative Materials provision of the code. You'll need additional exterior insulation in Minnesota. Earthbag basements are still experimental. Using ICFs would likely prove more expedient and realistic for most.
Thak you Owen,
I will let my husband know and continue on with the resurch. I will keep you psted as we move forward. Go-d bless, CarolAnn
mstricker3 years ago
I have been researching earthbag houses in hopes of building my parents a new house on their land in Northwest Missouri. They need something well insulated as it can get quite cold in the winter and is very hot and humid in the summer. Our funds are extremely limited so I was thinking the rice hulls make the most sense for us economically but was wondering how much they would be affected by moisture. Not only is it quite humid but they are in the Missouri River flood plain and also get some tremendous thunderstorms. I was planning on trying to build the foundation up with concrete rubble and gravel filled sandbags for the first few feet to help minimize the flooding damage. I would love some advice and encouragement on this. Will rice hulls work in this wet climate and any suggestions on building up the foundation? All and any advice appreciated and welcomed!
Owen Geiger (author)  mstricker3 years ago
We know of at least one earthbag house in Thailand made with bags of rice hulls. I was just in contact with him and his house survived the first rainy season. They get lots of rain and so what you're proposing is possible. I wouldn't risk it on a large, expensive home, but it should be fine on something small and simple. You have to be super careful the rice hulls don't get wet during construction, from roof leaks, leaks around windows, etc. It's taking a risk for sure. Maybe build a post and beam frame, finish the roof with wide roof overhangs and install the rice hulls later.

I would use broken rubble in a rubble trench and then fill lower bags with crushed gravel up to about window sill height.
Just a question but could you not use a Styrofoam sheet and attach it to the walls at all? Kind of like they do to a house that they are re-plastering?
Owen Geiger (author)  chrisandamanda3 years ago
Sure, that's the easiest way, but styrofoam is not good for the environment so I'm suggesting alternatives.
I mean polystyrene I know that they can come in sheets. I love this idea. I live in Canada would this style of building work in a cold wet climate?
Owen Geiger (author)  chrisandamanda3 years ago
Polystyrene is the same as Styrofoam. I show recycled polystyrene peanuts in this section view: http://earthbagbuilding.wordpress.com/2011/09/15/solar-pit-house-building-details/

So yes, this can work in Canada with a moisture barrier to protect it.
mike poind3 years ago
so what is the R factor of a earthbag wall/home useing soil & clay as bag fill
Owen Geiger (author)  mike poind3 years ago
A quick google check says .25 per inch. Typical earthbag walls once plastered are 18", so 18x.25=4.5 R-value. This is suitable for mild climates (where adobe houses are typically built). You can use insulated fill material in colder climates or add insulation on the outside.
armynavy174 years ago
Good instructable. I'm curious though, on your website you have plans for multistory homes, yet you don't explain how one would do the floor of one of these. That's my question, how would one build the floor of the second level?
you can do a loft type setup by having a portion of the second floor usable and use pillars to hold it up.
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