Archive for March, 2010

Using a standard-sized module can simplify the building design process. An even two foot module, for instance, is easy to plot on graph paper. This makes it easier to draw plans and calculate materials and costs.

Another benefit of 24” earthbag modules is increased overlap between courses. Many earthbag builders just fold over the ends of bags for expediency. This creates bags about 20” long and overlaps of about 5” assuming standard 18”x30” bags measured when empty. A 5” overlap is marginal in terms of creating a strong running bond. See drawing below.

Earthbag overlap: 20 inch versus 24 inch long bags

Earthbag overlap: 20 inch versus 24 inch long bags

In many situations you’ll want to use fewer bags to reduce waste and save money. You can do this by filling bags to capacity and sewing (needle and thread), stitching (galvanized wire) or pinning (nails or bamboo slivers(?)) bag ends closed. This saves bags, but also creates 24” long bags – a convenient sized module to work with – and 9” overlaps between courses for stronger walls.

Maybe you don’t want to spend extra time closing bag ends. Another way to get 24” long bags (when filled) is to buy longer bags. You can buy 18.5”x34” bags and fold the ends under. One supplier of these longer bags is Donald Davis Bags.

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We have added two new videos to our collection at www.earthbagbuilding.com that are definitely worth the time to watch. They are both slide shows set to music that are well assembled and very informative. They are listed at the bottom of this page.

The first is about building a school in Sierra Leone, Africa, which is also featured in an article where you can read more about this specific project.  This video can also be seen at the end of the article, or you can go directly to www.youtube.com to watch it.

The second video shows the construction of a lovely earthbag/cob house as part of an exhibit in a conference hall in Canada. It can also be seen at  www.youtube.com.

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I’ve seen some photos lately of structures with ‘thin bags’ where the earthbags were not filled all the way. My recommendation is to tamp the contents lightly as the bag is being filled. This just takes seconds and ensures the bag is filled to capacity so you need fewer bags.

Here’s the process:
1. Fill the bag about half way, fold over the bag (pull the top to one side) and tamp the contents lightly about 2-3 times.
2. Repeat the tamping after you’ve filled the bag to the desired level (experiment until you get find what works best). I fill each bag with the same number of buckets so each completed bag is the same size. This helps maintain level and an even running bond.

At this point you’ll have fat bags stuffed to capacity. The bag has been filled in place on the wall so now all you have to do is tilt it down in place, tight against the previous bag. Do not flatten the bags yet. Wait until the whole course is complete, then tamp. Depending on the size of the bag, each course will be about 5-1/2″ high after tamping, using this process.

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There’s still time to sign up for our roundhouse workshop in Thailand. About a dozen people have signed up so far.

The workshop is from April 19-25, 2010 in Sakon Nakhon, Thailand. The $500 cost covers lodging (now at a nearby resort due to a price increase at the planned for hotel), shuttle van and local tours of interest, such as the King’s royal sustainability projects.

Complete info for this workshop and for earthbag building apprenticeships is on my Workshops page.

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I am pleased to report that after a little more than a year of periodic work on the Ninos y Jovenes Earthbag Project in Mexico we have finally come to a successful point of completion!  We put a final coat of white roof paint on the outside, making the dome gleam like a jewel.

Here you can see our smiling faces with the finished dome in the background.

This project was only possible with the dedicated cooperation of the Lake Chapala Green Group,  the students and staff at the Ninos y Jovenes boarding school in San Juan Cosala, the many adults who came from both the Mexican and the foreign community to join our Saturday morning work force, and the generous donation of funds from many people to help with the cost of materials.

The project has satisfied every aspect of our intention to create a physical demonstration of an ecological way of building a small house for very little money. Many of the students who worked with us are native Huicoles who can now take what they have learned back to their communities to duplicate if  they want. We will be giving them printed instructions in Spanish with photos of the various phases of the project to help them remember the important steps in the process.

In addition to the students, we have worked along with at least five different Mexican adults, and as many people from the foreign community, who are planning to take what they have learned to other localities to build with earthbags. Some of these other projects are already well along, and they include both homes and a school in an alternative community near Guadalajara.

We have succeeded in having the dome project publicized in the media, with at least four articles having been published in local newspapers and magazines, both in English and Spanish. So is has been a huge educational success, and of course the dome itself will stand on the grounds of the school for a very long time I expect. It will be a beacon and a demonstration for all to touch and experience who stop by to see it. We intentionally left some of the interior of the dome free of plaster so that people can immediately see how it was actually built with the bags of soil.

We initially estimated that we would need to spend a little over $1,000 US to build the dome, and this would include the purchase of new bags, barbed wire, a custom steel door fabricated, windows and vents, wood to build a loft inside, soil delivered to the site, plastering materials, and some basic tools and tarps. In actuality, we spent closer to $1,500 US, mainly because we spent more for tools (and other reusable supplies) and plastering supplies than anticipated. If someone used soil dug on the site, found used bags and/or barbed wire, and found other used components, this cost could easily be halved.

The potential living space that this small dome provides is about 200 sq. ft., so that would be between about $4 and $8 per sq. ft…..not too bad in this day and age! And not only is the building quite ecological, with mostly soil as the building material, but it will be much better at conserving energy because the walls are so thick, so it would be more comfortable than conventional buildings to live in.

I want to thank everybody who has helped out with this project; it has been immensely worthwhile. You can see a complete set of photos and description of the process of building this dome at www.flickr.com and a slide show of the same pictures at www.flickr.com

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Earthbag workshop in Koh Phangan, Thailand

Earthbag workshop in Koh Phangan, Thailand

This is just a short summary of my experience teaching an earthbag workshop in Koh Phangan this weekend. We’ll be posting more later because Julien and Hubert, the hosts of the workshop and the driving force behind the project, are doing such outstanding work. They have a number of interesting, photogenic structures on their yoga retreat site where the workshop was held. They’re also developing innovative building techniques based on their site conditions on a tropical island. It’s very interesting to see people take the basic concepts, run with it and create new things.

Workshop participants came from Canada, Europe, numerous areas of Thailand and other places. Most participants said they were planning earthbag projects. One group of seven, for instance, was sent by their employer to learn the techniques so they could build an earthbag coffee shop. Most were planning on building their own homes.

The workshop included seven PowerPoint presentations, whiteboard tech talks combined with lots of questions and answers, a tour of their buildings, and hands-on practice building a retaining wall.

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Group will spend spring break teaching how to construct temporary housing

by David Hill | Staff Writer, www.gazette.net

It’s Sunday afternoon in College Park’s Calvert Hills neighborhood, and Desta Anyiwo — a 23-year-old student at the University of Maryland, College Park, — is being peppered with questions from curious onlookers.

He explains that he and a group of volunteers are building an eight-by-eight-foot structure through earth bag construction — the use of heavy bags of dirt, sand and other materials as building blocks for temporary housing. A completed structure, he said, can sustain heavy rain and high winds.

After a major earthquake struck Haiti on Jan. 12, killing more than 200,000 people, Anyiwo decided earth bag construction might be cheap and reliable enough to help the victims, many of whom are now homeless or live in tents. On Saturday, he and a group of about 20 people will leave for Haiti, where they will spend a week demonstrating, assisting and teaching Haitians how to build their own shelters.

“They’re about to have a rainy season right now [in Haiti],” said Anyiwo, who helped organize the trip with alumni and faculty from Howard University in Washington, D.C., some of whom had previous humanitarian experience in Haiti. “Some people are raising money to send tents down … [but] this is a way more effective way of helping people.”

About 13 UM and three Howard students will make the trip, along with a handful of engineering professionals. Their main goal is to teach earth bag construction to Haitian residents and students in hopes that they’ll be able to teach others to use it for years to come.

Earth bag structures have been built in Haiti and in parts of Africa and the southwestern United States, but are still relatively rare, said Tom Marable, a professional engineer on the project. Anyiwo’s group spent three days in College Park building a test shelter to make sure they had experience with the method.

The earth bags were flattened and carefully placed, with each layer of bags held together by barbed wire and plaster or stucco. Finished structures are usually topped with a tarp, bamboo or thatch roof.

“[The materials] depend on what’s available in their area,” said Vicki Bleus, president of Washington, D.C.-based Phoenix Contractors Inc., which has lent engineering guidance. “If they’re near [Haiti’s capital city] Port-au-Prince, they might have access to crushed rubble.”

The group plans to bring about 4,000 polypropylene bags to Haiti, but all building materials will have to be found in the country. The College Park prototype required about 400 bags of dirt, so they hope to have enough bags to do a week’s worth of demonstrations before leaving March 20.

Each student paid about $800 to make the trip, while the professionals paid $1,000 each, Bleus said. Anyiwo said he plans to make a second trip to Haiti this summer.

The trip will have added personal meaning for UM sophomore Joshua Jean, who is among several Haitian-Americans who have volunteered. This will be his first time visiting the nation where his parents were born.

“Most of my family is still there, so I thought this would be a good opportunity to help,” Jean said, adding that all his known relatives survived the quake. “Everyone’s OK, but still, there’s extensive damage and there’s going to need to be repairs for years to come.”

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From www.raglan.net.nz:

Want to know more about greener building techniques? Solscape Eco retreat at Manu Bay, Raglan are running an earth bag building course workshop from 16th-30th March. Read on to learn more about earth bag building. From the Raglan Chronicle, October 2009, by Edith Symes:

It looks like a teletubby house, or maybe a mud igloo, but an intriguing “earthbag” building that’s taken shape at Solscape eco-retreat at Manu Bay over the past few weeks is no frivolous venture.

The building, one of only three so far in the country, is being touted as an exciting possibility in the search for affordable housing. It’s both “low cost” – about $2000 for the materials – and “high performance”, accommodating two to three people.

The novel construction is the result of an earthbag building workshop which has kept both locals and foreigners busy, in rain and shine, at Solscape for the past few weeks. By late last week the 10 square metre sleepout, which has the huge advantage of needing no permit, looked all but complete with its thick earthen walls ready to be earth plastered, and rounded window spaces fashioned from a recycled gas bottle.

“Heaps of people have been coming to check it out,” says Solscape’s Phil McCabe who’s been heavily involved in the workshop himself. Phil first saw the unique design at the ecoshow, and arranged for the local workshop as a way to experiment with one possible technology for alternative ways of living.

“This is a great possibility for affordable housing or papakainga (Maori using land),” he enthuses. “It’s about using not a lot of cash but a lot of human energy.” For instance, about 20 cubic metres of earth was first dug out from a nearby hillside. “It was good hard work,” says Phil, pointing out that about 95 percent of the “very simple” materials used – earth, hydrated lime, recycled paper fibre and cow dung – are locally sourced.
Using minimal cement, very little transport and absolutely no processing and packaging, the earthbag structure represents what Phil describes as “low embodied energy” which fits in neatly with Solscape’s eco philosophy. Another earthbag building is planned on site, possibly next year, close to the first one.

The buildings have the added advantage of using no cut trees and no nails except in the construction of this first one’s mezzanine floor, adds Phil. While tutors Bryan Innes and Bomun Bock-Chung led the Manu Bay workshop, Phil reckons anybody with a bit of building experience can do it for themselves. “It requires only one person with some understanding (of the process) and others can turn up and lend a hand.”

Similar to a rammed earth house but without the heavy plywood structure, the dome-like earthbag building relies for its form on 500 metre polypropylene tubes , of the kind stock feed bags are made of, and uses nothing else except barbed wire and raw materials. The tubes are stuffed with a dry mixture of earth and cement. No water is added because enough moisture comes from the soil in the mix, explains Bryan who’s right into sustainability education. Of the 50 or so cylindrical layers or “courses”, adds Phil, only about 15 have cement content. The rest are stabilised with a dry sand mix.

The earthbag system was designed by a Californian company called Cal Earth but only the tubes are new, says Bryan. Similar domed buildings have been around for hundreds of years and have the structural strength of an igloo, which also uses the same material for its roof as its walls. Others have been built for emergency shelter in such places as Iran.

But earthbag buildings are “better than bomb shelters”, Bryan says, because they’re designed to work with weight, using the rammed earth cylinders with barbed wire between them. And they’ll last “forever”.

For information about the next course running 16th-30th March contact Jo on 021 739 398 or email joATecoshow.co.nz

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From time to time we’ll post answers to readers’ questions.
Q: How do earthbag structures compare to military sand bag bunkers?

A: We know sand bags have been in use by the military for a very long time, possibly as long as 250 years. See Earthbag History Footnote.

We also know sand bags (earthbags) are still widely used by the military and in flood control due to their strength and practicality (simplicity, reliability, affordability, rapid delivery, etc).

Like their military counterpart, earthbag buildings are very strong and can be made even stronger with the use of added reinforcement. In the simplest terms, it’s like military sand bag bunkers with reinforcing — rebar pins, plaster mesh, plaster, reinforced bond beam and barbed wire. Not all earthbag structures require extra reinforcing, but it is possible to design safe, affordable earthbag buildings for virtually any environment, including hurricane, tornado and earthquake regions, and war zones.

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This post was contributed by Patti Stouter.

What building materials are available near a disaster site?  Broken pipes, tubular steel, corrugated metal roofing?  All of these can be used to stiffen earthbag walls.

Corners of buildings are especially liable to earthquake damage.  Horizontal motion in a quake can be twice as powerful as vertical motion.  This motion is usually directional, and because it acts differently on walls facing and parallel to the motion, there is great stress on corners of buildings during quakes.

Pieces of tubular steel, angle iron, pipe, or roofing scraps can all add strength to earthbag walls.  The hardest question is can they be securely attached at a corner?  Metal brackets can be screwed or welded to connect tubes or angles of metal.  Pipe fittings may be available.  But corrugated metal may be the easiest to use.

If corrugated metal cannot twist, it is very strong to resist pressure across the corrugations.  Sandwich it between layers of earthbags (tightly), and it won’t be able to twist.  It can keep a long straight wall from bowing out.  Overlap it and pin it well at a corner and it can keep the walls from moving apart during a quake.

This kind of brace may be very helpful low in a building that does not have a concrete foundation.  It may be useful higher up to strengthen corners with windows nearby, and allow clean corners to be built without piers.

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