A couple in Alberta, Canada have built what appears to be a very nice little dome sauna with earthbags. They say that they have only spent about $125 (mostly on bag material), with the rest of the materials either dug from their property or gleaned from dumps, etc. The bags were first covered with a layer of cob, then finished with an earthen plaster.

One thing that is different than most earthbag projects that I have seen, is that they used a clear plastic tubing material, instead of the usual woven polypropylene. My guess is that this was 6 mil polyethylene, which is not breathable. I wonder if the damp sand/clay mix inside the tubing will ever dry out. They say that the compacted material is about as hard as concrete, so in this little sauna, it may not matter. With all of the steam created inside, ordinary bags would allow the fill to become moist anyway. They built a rocket stove to heat the space, so I’m sure it gets plenty hot in there.

You can read more about how they built this at earthbagbuilding.com.

I am very pleased to announce that a new forum has been created where people can share information, photos, videos, questions, and network socially…all about earthbag building! It is The Earthbag Building Network and it is very easy to register and become a participant. I just did, and I hope that many of you will also.

Paul McMaster is the founder of this network, and he says, “I started the EarthBag Network after deciding to build with earthbags and wanting to help more people connect and find out how to do the same.”

Thank you Paul!

Jorge Dominguez has been building earthbag  houses in Hawaii for  some time, and he recently emailed me some of his thoughts about this way of building as it relates to durability, financing, and insurance. I think that he has touched on some very important issues that I would like to share with you.

“I was originally against asking banks for financing for earthbag structures. I don’t think I am going to do it for my experimental home on the Big Island, but I think that for bigger projects there is no way to do them without some kind of loan from a bank. My guess is that if I ask for a loan for an earthbag building, it is going to get rejected in 5 minutes.  They don’t care much about the process of building and the environmental benefits of earthbags. All they care about is the bottom line, whether they can make a profit or not.”

“The current real estate meltdown is proof that something is inherently wrong with the way homeowners get financing from banks. It seemed like almost everyone was playing a speculators game with homes that were not meant to last long. It appears that banks favor building with economies of scale using prefabricated materials. Sure, this way of building can guarantee low costs in the short run, provided that transportation costs do not rise that fast. Crossing fingers that oil prices will not go over the roof can make this model look good. But what nobody seems to be questioning is how long do these homes built with prefabricated materials last.”

“The typical definition of homeowner is somebody who gets financing from a bank, and moves in with his family to the new home after having been approved for a loan and giving a small deposit. But let’s be realistic: this is not owning a home, more accurately you are a home debtor.”

“Banks should give priority to homes that have a long life. If your home begins to deteriorate in 20 years, we cannot call that a fixed asset. A big incentive for owning a home is  creating value for your descendants. What is the point in signing up for a 30 year loan, if the home is going to last only 20 years? Sure, someone can tell us that you can extend the lifetime of a home with the proper maintenance, but is it common to see a home that lasts 100 years? What about ancient culture’s way of building? With very little technology, there is living proof of still standing structures built by the Aztecs, Greeks, Romans, Mayans.”

“We would like banks to start financing earthbag building, because not only it is environmentally correct, but it is a super durable material. Banks should not focused entirely on the big guys with their economies of scale. They should think outside the box, and provide funding for do-it-yourself builders. Earthbag or super adobe building is extremely economical on materials. The only real costs are the hauling of earth, sand and gravel short distances. These materials are so abundant in nature that there is no risk of depleting natural resources like is the case with wood.”

My sister who also lives in Hawaii and is a professional real estate appraiser had this to say on these issues:

“I agree with you whole-heartedly about the sustainability issues around earthbag and other alternative building practices.  It does seem crazy to build with wood where the moisture levels are so extreme, and termites are prevalent.  All the lava is used for rock walls, and I haven’t seen one home made out it. I have seen first hand what a short time of negligence can do in this climate to traditional homes.”

“Unfortunantely, what the banks are looking for is conformity and security, especially now with the mortgage crisis that is still spiralling down here, with tons of short sales and foreclosures and more yet to come.  Of the properties for sale in my subdivision 40-45% are distressed properties.”

” Conformity is good for banks and appraisers because it makes comparison simple and is a good way to conclude value.  Examples of homes that are considered to be less market approved of are A-frame homes, domes, and those built with alternative building materials.”

“County codes and regulations are a kind of Bible for banks and if the local planning department accepts a building it is considered to be okay.  In approaching a bank for a loan on an earthbag home your best bet is to have as much blessing and documentation from the planning and building departments as you can get.  You will be more likely to secure a loan if you have more than 20% down payment.  No doubt the loan will be at a higher interest rate due to “risk” factors of market acceptance, and you will not get the loan amount that a conventional home would.  Domes, for instance, require a discount in the appraisal for what is called “functional obsolescence” which means most buyers would reject it.  It therefor is not as functional in the arena of buyers and sellers.  This discount can be 10% of the value or more, so you would have to anticipate this.”

“There are more signs that the green movement is becoming more mainstream.  There are now classes for appraisers about green homes and commercial buildings and it is gaining momentum.  Accepting alternative materials is a next step.”

I recently wrote an article about living walls for GreenHomeBuilding.com, and in doing the research for this I came upon an interesting approach to creating a kind of living wall or retaining wall using geotextile materials. Basically, loosely woven bags filled with a growing medium can be stacked to form walls that then support plant growth.

One company in particular, www.filtrexx.com, has been selling various systems for doing this for some time. This is a green alternative to hard-faced walls, and can create walls that are either completely vertical or slope up to 2:1. A variety of vegetation can be supported this way, depending on the location and purpose of the wall. They say that this is faster to install than conventional block materials used in retaining walls.

But if you look at the basis of the concept, it is not that different than building with earthbags: bags of material are stacked to form walls. But in this case, the bags are then protected by the plants that grow out of them, and this vegetation becomes the exterior interface with the environment, providing oxygen, filtering the air, and looking beautiful.

So how might this idea be utilized for buildings? Obviously the main issue is the moisture that inevitably will migrate into and through the wall to the interior space…unless there is some way to stop it.

One approach might be to build the earthbag structure as is frequently done, with compacted soil, and then cover this with a waterproof membrane to protect it from intruding moisture. A second skin of a “living wall” could then be applied over the membrane, both as protection for the earthbag structure, and as an insulating layer.

This would create the ideal situation for climate-responsive housing, where the inside is composed of thermal mass materials, and the shell of the structure is insulated to keep the interior from loosing its comfortable temperature.

Besides using the geotextile bags, it is also possible to use one of the variety of systems that have been devised for creating living walls that are attached to buildings, as shown above. Many of these sophisticated systems automatically provide the necessary water to maintain the plants, so there is very little maintenance over time.

I am pleased to announce that www.earthbagbuilding.com is now available online in 35 different languages. With the simple addition of a Google “Translate” box as part of the main menu, you can now choose to read all of the text on any given page in your language of preference. Once the new page is created (it only takes a few seconds), then the entire site can be browsed via the standard menu and all subsequent pages are also presented in translation. Amazing!

This should make the information more accessible to the millions of people around the world who might benefit by it.

Kikuma Watanabe is an associate professor of architecture at Kochi University of Technology in Japan and is responsible for the design of several wonderful earthbag projects around the world. He collaborated with Akio Inoue (a Japanese professor of philosophy) on designing an eco-village near Lake Victoria in Uganda, and they have helped the Africans build the first model unit of this village.  A detailed account of this project can be seen at earthbagbuilding.com.

Kikuma Watanabe has a refined sense of design that enables him to combine a variety of  forms into intricately balanced works of art. Elongated domes might be connected with vaulted corridors and intersecting circular forms that create fascinating patterns. These forms are often rooted in the local culture with unique features, such as raised thatched cupolas.

Above is one of the nearly finished units of the Uganda Eco-village.

In Jordan, he designed a cultural center for the Al-Jawasreh Society that has three architectural components: Jordan’s traditional stone building, modern reinforced concrete, and earthbag domes. As with most of his designs, this one integrates the building forms intimately with the landscape to create a unified whole.

Above is the plan of a model unit in the ISEGERO village, also being built in Uganda. The pink circle is the model dome that is being built there.  After the model dome is completed, it will be used for a meditation room. There is a small earthbag house with bedroom, shower room, and toilet.

Kikuma Watanabe has also desiged a couple of Mandala Villages for India and Afghanistan that demonstrate how he interweaves functionality with sublime design. When attempting to assist disaster-stricken areas, local people were very pleased with village planning that was shaped with mandalas. These plans may assist in healing the traumatized people.

We often get questions from people wondering how many bags they need to have on hand for some particular project. Is there a formula to figure this out?

First you need to calculate the total square footage (or square meters) of  the wall you intend to build. This can be done by simply multiplying the length times the height, and then to be precise, you can deduct the size of the windows and doors from this…but I usually don’t do this because it is better to over-estimate how many bags you might need, and also, you always need some partial bags to keep the brick pattern going.

If your wall is curved you’ll need to figure out the running length of the wall by either making a scale drawing and measuring the length that way, or in the case of a circle you can use the formula Length = 3.14 X the diameter for this.

Figuring out the surface area of a dome is obviously more complicated, partly because there are many shapes for domes. If the dome is close to hemispherical (not recommended for structural reasons) the formula would be 3.14 X the diameter squared. If the dome more closely resembles a cone, then the formula would be 3.14 X the radius X the radius plus the length from circle at the base to the top of the cone. Either of  these formulas could be used to estimate approximately what the area of your dome might be, especially, if that total is then padded by not deducting openings, or simply rounding upward.

As far as bag coverage goes, it depends on the size of the bag how much square footage it will cover. I used what were labeled 50 lb. rice bags to build my house. These measured roughly 5″ X 20″ when laid in a wall and compacted. That is approximately .7 of a sq. ft.  A nominal 100 lb. bag might actually be considerably larger than what I used, so you’ll need to run some tests to determine what kind of coverage to expect. The 50 lb. bags I used measured about 18″ X 30″ when laid flat.

Once you have figured out what the area of one bag might be after it is filled and tamped, then you can  divide that figure into your total wall space to get the total number of bags needed. For instance, with the 50 lb. bags that I used, you would divide the area by .7 to get the total number of bags needed. In this case, for example, a 100 square foot wall would require roughly 143 bags.

Happy calculating!

In 2005 there was much publicity and delight regarding a lovely earthbag clinic built in a small town in the Philippines. This was a project of Illac Diaz and several organizations there. You can see the finished building below.

Since then it has been privately reported that the building has fallen into disrepair. Some photos accompanying the report clearly show that this is the case:

So what happened? Here is what I think. You can see in the photo below how the workmen are applying mud to the cement-stabilized earthbag structure.

Obviously the final layer of plaster did not adhere to the mud fill that was applied. Plants are now growing naturally in this earthen medium; the seeds or roots may have been present at the time it was applied.

What this indicates to me is that the intermediate mud plaster was a mistake, and it should have been replaced by more stabilized material like what was placed in the earthbags. Then the final color coat of compatible plaster would likely have remained intact, and nothing would be growing up there.

It is a sad commentary that despite such a lovely structure having been built, there is not sufficient interest, or follow-through to remedy the situation and salvage the entire building.

To read about the entire project and see  more photos see www.earthbagbuilding.com

According to an article entitled “Eccentric Aesthetics: DIY Eco-Friendly Earthbag Homes” posted at dornob.com, the phrase “form follows function” has morphed in meaning over time and is, perhaps rightly, open to interpretation. One interesting extension of this idea is that the form of a building can follow the functions of its constituent parts – that the visual result can reflect the process of construction and that this, in turn, makes the architecture more educational or “honest” – a way to learn the history of a building simply by taking a look at how it was made.

In addition to their do-it-yourself, easy-to-build and other sustainability-related benefits, “earth bag” homes – constructed of bags filled with local dirt, mud, sand and/or rock – are also potentially extremely expressive as works of design. Their structural properties and the ways in which they are stacked certainly preclude some design possibilities but they enable others.

The end product reflects not only the more universal properties of sand-and-dirt-built structures but also can indicate individual stylistic preferences and regional building practices. The final appearance is generally curved, organic and assymetrical – not things we are used to in home design – but invariably are anything but boring.  All in all, they have a great deal of expressive potential for something so cheap, easy and fast to build – if nothing else as an eccentric guest house or secondary rural cabin.

Sourabh Phadke in India has been quite productive lately in publicizing earthbag building in various ways.  He is involved with a school there, where they have been experimenting with many aspects of natural building and green living, from compost toilets to creatively using recycled plastic bottles to earthen plasters over earthbag walls. Much of this has been documented with short educational videos that he narrated and put up on You Tube. You can see these at www.youtube.com/user/antiismistix.

Sourabh sent me his latest work, which is a charming slide show in PDF format called “The Rocket & the Rabbithole”.  It outlines why and how they created a two-classroom school building with earthbags. This is now available for viewing at earthbagbuilding.com

Thank you Sourabh for all of your wonderfully entertaining and educational efforts!