Kelly Hart - Earthbag Architecture: Building Your Dream with Bags

Foreword

Ten years have elapsed since Kelly Hart and I decided to create EarthbagBuilding.com, and shortly thereafter Earthbag Building Blog (later renamed NaturalBuildingBlog.com). Its been a pleasure and honor working with Kelly. What started as a basic idea to spread the word about building with bags has grown by leaps and bounds as more people world-wide seek out lower cost, more sustainable building options. These two websites combined now average about 8,000 readers each day. The reasons for this growth are many. Escalating construction costs is the primary motivator for using alternative building methods such as earthbags. Factory made materials such as cement, steel and brick have become much more expensive and so many people simply cannot afford to build their own homes with these conventional materials.

Along with the rapid growth in popularity have come many innovations. The simplicity of natural building lends itself to creativity and experimentation, so builders often try new things. Being actively involved in every aspect of this movement means Kelly and I get to hear about countless innovations and share the best ideas with our readers.

Ten years ago the main earthbag options were building domes and other small, simple designs with subsoil and stabilized subsoil in polypropylene bags. There were very few earthbag building books, websites, workshops and trainers at that time. Kelly had been experimenting with scoria bag building, but few other main earthbag authors and builders have picked up on the idea, despite all the advantages of building with scoria -- lightweight, super insulating, easy to work with, faster, fire and pest resistant, etc.

The pace of earthbag innovation has greatly accelerated with a greater Web presence. This has made it much easier for people to discover the benefits of building with bags. Its no longer necessary to attend a workshop or buy a book; most building details are now clearly explained on our websites. Over the years our sites have documented all the best earthbag building projects, materials and methods. Weve continuously added project profiles, house designs, images, videos, testing reports, articles and other related resources. We now have thousands of pages of free information.

Of all the changes from the last 10 years perhaps the most exciting have been improvements in building methods. These innovations can have a far reaching impact that effects how buildings are constructed for many years to come. Using lightweight scoria instead of heavier materials may make it possible for less muscular owner-builders to build their own home. This is but one of many such examples. Heres a sampling of earthbag innovations and developments over the last 10 years:

• Greater use of lightweight, highly insulating materials such as scoria, pumice, perlite and expanded clay granules and rice hulls;
• Engineer Fernando Pacheco developed hyperadobe building using raschel mesh tubing. Both Kelly and I are big fans of building with mesh bags and tubing, and have written extensively about this exciting development. The cost of the mesh material can be around one-quarter of the cost of poly bags, plus the mesh is ideal for binding with plaster;
• Eternally Solar/Dr. Andertons sand bag building method;
• Patti Stouters hyperwattle method;
• Mechanized building to speed construction has become more popular;
• Many new fill materials have been proposed and experimented with: foamed geopolymer, hempcrete, vetiver/lime, vetiver/clay, woodchip/clay, crushed limestone, lime or gypsum stabilized soil, caliche, mine tailings;
• Confined earthbag with post and beam frame;
• Thin wall earthbag building for speed and ease of construction;
• Rainscreen to protect earthbag domes;
• Earthquake and hurricane resistant construction methods such as pinning walls with rebar;
• Low cost, alternative bond beams, lintels, foundations and many other details;
• Making uniform earthbags using a wooden form as in Coron, Philippines;
• Earthbag cool pantries, root cellars, water tanks, retaining walls, ponds.

Owen Geiger, April, 2015

Introduction

In 1996 my wife Rosana and I were traveling around the Southwestern United States in a 40 foot bus I had converted into a traveling home and video production studio. I was collecting information and video footage for a documentary program called A Sampler of Alternative Homes: Approaching Sustainable Architecture. Somebody I talked to asked me, Have you heard of earthbag building? I hadnt, but I was determined to find out more about it, as it seemed like it should be covered in my program.

I soon discovered that an Iranian born architect named Nader Khalili was responsible for promoting the idea of making buildings by stacking bags, or tubes, filled with soil. He called this technique Superadobe. I arranged to meet him at his experimental compound, CalEarth (The California Institute of Earth Art and Architecture), in the California desert, to get a first hand introduction to the building technique. There I found an interesting collection of odd-shaped structures, mostly fashioned by stacking coils of large plastic tubing filled with soil. Khalili himself was a charismatic visionary with the zeal and drive to manifest his visions.

Around this time, I also visited a former student of Khalilis institute, who had built herself a small domed house and art studio using the Superadobe technique in Arizona, and footage of her explaining how she and her son had done it was used in the video program.

As we roamed around the American Southwest in our bus, we were always looking for beautiful places where we could park, and possibly develop landing pads for recurrent visits. One such spot turned up at a high alpine valley in Southern Colorado. The scenery was spectacular and the land was cheap, so we bought a small bit of acreage that actually had water, sewer, and electricity within easy range for hooking up.

The only hitch with just parking our bus there and enjoying life was that the property owners association that governed what could be done on the land had rules that expressly denied this. It would be possible to live in our bus while building a house, however, so we started to think about doing just that. My mind went back to the earthbag building I had seen, and I convinced Rosana that we could design and build an experimental home with earthbags, and do so quite cheaply.

Fortunately, beyond the regulations applied by the homeowners association, the county had not adopted restrictive building codes. This made such experimental construction much more feasible. We designed a rather unusual looking plan that combined two domes with a central connecting space between them, and offered this to the committee that reviewed plans for the association. I was a little surprised that they accepted these plans without modification, so we were free to begin construction. I will describe the process of building this home in considerable detail later in the book.

Since completing that earthbag house (in about 2000), I have engaged in a number of other earthbag building projects, including a small dam for a pond, a large vault for a garage/shop/office complex, a small amphitheater project, a recessed pantry, and several independent small domes. I will describe all of this building as the story unfolds. I have learned a lot from all of this experience, that I will share with you.