Earthbag Architecture: Modern Mud Domes for Sustainable Living
Last Updated: Mar 28, 2025For millennia, humans have built shelters out of the mud beneath their feet. Many modern-day homeowners, particularly those of us who live in the west, might consider the idea of constructing a home out of clay or mud a primitive and anti-hygienic building technique. (Rammed earth construction is seemingly an exception.)
Earthen architecture, however, offers several sustainability and health advantages. Because the primary construction material, raw clay soil, is usually located directly on the building site, earthen architecture has a very low embodied energy footprint. Earthen homes also have high thermal mass. Earthen architecture can incorporate passive solar design to reduce artificial heating and cooling requirements. Earthen houses also protect interior air quality, and when partnered with mineral and earthen plasters, will not emit any VOCs into your home.
Table of Contents
- What Are Earthbag Homes?
- What Bags Are Used For Earthbag Homes?
- Why Build Earthbag Homes?
- Earthbag Construction
- How Do You Keep Earthbags From Rotting?
- How Long Do Earthbag Homes Last?
- Building An Earthbag Home
- What States Allow Earthbag Homes?
In terms of structural strength, earthen architecture is often constructed using techniques that ensure the home lasts for hundreds of years. In the Hadramut region of Yemen, whole cities of earthen skyscrapers (up to nine stories tall) continue to house a growing population.
In the mountains of Guatemala, Kyle and Jolene were looking for an affordable and sustainable way to build a home. They discovered earthbag architecture, otherwise known as the SuperAdobe. They found the idea of making a home almost entirely from materials found on the site of their rural homestead attractive.
"We decided on a SuperAdobe dome because we wanted to learn a new earth-building style, and had great contacts in the area with lots of experience building earthbag structures," they say. "We organized a workshop together and brought friends from all over North America to help and learn.
We wanted to build a unique off-grid tiny home that could be a module in a larger structure later on. The fact that we could put up a dome quickly, without needing to build a roof (the walls are the roof), was a nice factor."
What Are Earthbag Homes?
In southern California, the Iranian-born architect Nader Khalili developed a unique earthen architecture technique called SuperAdobe. The technique was originally designed as a prototype for NASA to create theoretical human settlements on the Moon and Mars. But, Khalili's SuperAdobe later became an affordable and practical housing alternative for refugees, people affected by natural disasters, and the homeless.
Today, tens of thousands of SuperAdobe earthbag homes have built around the world in different climates. This unique earthen building technique offers a pathway to affordable, environmentally friendly, and aesthetically unique dwellings.
One of the unique aspects of earthbag and SuperAdobe homes is the simplicity of construction. Khalili designed the building process to require minimal building materials. According to the California Institute of Earth Architecture which Khalili founded in 1991, the only materials needed to build a SuperAdobe dome are:
- Synthetic, low UV (ultra-violet) resistant degradable sandbags
- Four-point, two-strand, galvanized barbed wire
- Shovels
- Tampers
- Soil
- Water
The construction process is also very DIY-friendly and intentionally simple. SuperAdobe homes, then, can be built by virtually anyone with access to sandbags and a bit of soil.
The thick earthen walls act as a thermal mass, allowing the structure to slowly absorb the solar heat during the day and emanate that heat into the home during cooler evenings. This thermal mass can drastically reduce the need for artificial heating and cooling, which accounts for almost 50 percent of the total energy use in modern-day homes.
Earthbag homes are also structurally sound and resilient. When developing this technique, Khalili incorporated modern engineering concepts in structural design, including base-isolation and post-tensioning. The coils made from compressed earth within the polypropylene bags give the walls compressive strength.
Meanwhile, the barbed wire gives the entire structure tensile strength. The earthen nature of the walls provides insulation and natural fire resistance. Earthbag homes have passed several rigorous earthquake code tests in California. The typical dome structure, which is a common option for SuperAdobe construction, is one of the most robust natural geometric structures.
Earthbag Construction
Earthbag homes are usually built with the polypropylene bags commonly used as sandbags during floods. These types of bags are also widely used for feed sacks and can be sourced from recycled sources. The California Institute of Earth Architecture recommends bags specially manufactured as long tubes, which can be cut to the specific length of your wall. The Institute offers affordable SuperAdobe bags that are sold by the roll. A 1,000-yard SuperAdobe roll of polypropylene bag costs $842. If you are having trouble sourcing polypropylene feed sacks or bags, you can also use burlap bags, though these do need to be coated with plaster.
How Do You Keep Earthbags From Rotting?
Earthbag homes, like all earthen architectural techniques, can last for hundreds of years as long as they are protected from rain and water. To achieve the necessary protection:
- For dome-style homes, a thick cement-based plaster is necessary.
- For traditional linear walls, a roof with extended eaves can protect the earthen walls from driving rain.
- Of course, a stem wall made from rock, cinder block, or some other impervious material will also protect earthbags from surface water.
How Long Do Earthbag Homes Last?
When protected from the rain and surface water, earthbag homes can easily last for a lifetime. If the earthbags are not plastered on the exterior, the UV rays from the sun will eventually disintegrate the polypropylene material. However, this can be avoided by merely covering the walls in a cement, earthen, or mineral-based plaster.
Kelly Hart, an expert earthbag builder, believes that earthbag homes will easily last at least a century. The polypropylene bags can even be burned or allowed to disintegrate because they play no role in the overall structural strength of the home.
Kyle and Jolene say the earthbag or SuperAdobe construction methods "is an awesome and fun way to build, but it has its limitations." For other homeowners wanting to try this method of building, Kyle and Jolene advise, "Plastering the interior spaces can be a challenge. Know your local climate and soil type. Take your time before building to really get to know your site and observe nature's patterns on the land. This will really help you out in the long run and is worth the extra patience."
What States Allow Earthbag Homes?
As with most alternative building techniques, navigating the building codes and laws for earthbag homes can be tricky. Because of the relative "newness" of this building technique, many local building codes will not recognize this earthen building technique. To date, code-approved Super Adobe houses have been built in Hawaii, California, Utah, Arizona, and Kentucky. For homeowners wanting to make an earthbag home in a jurisdiction that doesn't currently allow for this type of construction, getting an engineer's "stamp of approval" can help. Also, educating officials in charge of your building code might be a strategy worth exploring.
Tobias Roberts
Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.
